diff --git a/Lib/gzip.py b/Lib/gzip.py index 5b20e5ba69..af32b171f6 100644 --- a/Lib/gzip.py +++ b/Lib/gzip.py @@ -21,6 +21,9 @@ _COMPRESS_LEVEL_TRADEOFF = 6 _COMPRESS_LEVEL_BEST = 9 +READ_BUFFER_SIZE = 128 * 1024 +_WRITE_BUFFER_SIZE = 4 * io.DEFAULT_BUFFER_SIZE + def open(filename, mode="rb", compresslevel=_COMPRESS_LEVEL_BEST, encoding=None, errors=None, newline=None): @@ -94,7 +97,7 @@ def read(self, size): read = self._read self._read = None return self._buffer[read:] + \ - self.file.read(size-self._length+read) + self.file.read(size-self._length+read) def prepend(self, prepend=b''): if self._read is None: @@ -118,6 +121,21 @@ class BadGzipFile(OSError): """Exception raised in some cases for invalid gzip files.""" +class _WriteBufferStream(io.RawIOBase): + """Minimal object to pass WriteBuffer flushes into GzipFile""" + def __init__(self, gzip_file): + self.gzip_file = gzip_file + + def write(self, data): + return self.gzip_file._write_raw(data) + + def seekable(self): + return False + + def writable(self): + return True + + class GzipFile(_compression.BaseStream): """The GzipFile class simulates most of the methods of a file object with the exception of the truncate() method. @@ -182,6 +200,7 @@ def __init__(self, filename=None, mode=None, if mode is None: mode = getattr(fileobj, 'mode', 'rb') + if mode.startswith('r'): self.mode = READ raw = _GzipReader(fileobj) @@ -204,6 +223,9 @@ def __init__(self, filename=None, mode=None, zlib.DEF_MEM_LEVEL, 0) self._write_mtime = mtime + self._buffer_size = _WRITE_BUFFER_SIZE + self._buffer = io.BufferedWriter(_WriteBufferStream(self), + buffer_size=self._buffer_size) else: raise ValueError("Invalid mode: {!r}".format(mode)) @@ -212,14 +234,6 @@ def __init__(self, filename=None, mode=None, if self.mode == WRITE: self._write_gzip_header(compresslevel) - @property - def filename(self): - import warnings - warnings.warn("use the name attribute", DeprecationWarning, 2) - if self.mode == WRITE and self.name[-3:] != ".gz": - return self.name + ".gz" - return self.name - @property def mtime(self): """Last modification time read from stream, or None""" @@ -237,6 +251,11 @@ def _init_write(self, filename): self.bufsize = 0 self.offset = 0 # Current file offset for seek(), tell(), etc + def tell(self): + self._check_not_closed() + self._buffer.flush() + return super().tell() + def _write_gzip_header(self, compresslevel): self.fileobj.write(b'\037\213') # magic header self.fileobj.write(b'\010') # compression method @@ -278,6 +297,10 @@ def write(self,data): if self.fileobj is None: raise ValueError("write() on closed GzipFile object") + return self._buffer.write(data) + + def _write_raw(self, data): + # Called by our self._buffer underlying WriteBufferStream. if isinstance(data, (bytes, bytearray)): length = len(data) else: @@ -328,9 +351,9 @@ def close(self): fileobj = self.fileobj if fileobj is None: return - self.fileobj = None try: if self.mode == WRITE: + self._buffer.flush() fileobj.write(self.compress.flush()) write32u(fileobj, self.crc) # self.size may exceed 2 GiB, or even 4 GiB @@ -338,6 +361,7 @@ def close(self): elif self.mode == READ: self._buffer.close() finally: + self.fileobj = None myfileobj = self.myfileobj if myfileobj: self.myfileobj = None @@ -346,6 +370,7 @@ def close(self): def flush(self,zlib_mode=zlib.Z_SYNC_FLUSH): self._check_not_closed() if self.mode == WRITE: + self._buffer.flush() # Ensure the compressor's buffer is flushed self.fileobj.write(self.compress.flush(zlib_mode)) self.fileobj.flush() @@ -376,6 +401,9 @@ def seekable(self): def seek(self, offset, whence=io.SEEK_SET): if self.mode == WRITE: + self._check_not_closed() + # Flush buffer to ensure validity of self.offset + self._buffer.flush() if whence != io.SEEK_SET: if whence == io.SEEK_CUR: offset = self.offset + offset @@ -384,10 +412,10 @@ def seek(self, offset, whence=io.SEEK_SET): if offset < self.offset: raise OSError('Negative seek in write mode') count = offset - self.offset - chunk = b'\0' * 1024 - for i in range(count // 1024): + chunk = b'\0' * self._buffer_size + for i in range(count // self._buffer_size): self.write(chunk) - self.write(b'\0' * (count % 1024)) + self.write(b'\0' * (count % self._buffer_size)) elif self.mode == READ: self._check_not_closed() return self._buffer.seek(offset, whence) @@ -454,7 +482,7 @@ def _read_gzip_header(fp): class _GzipReader(_compression.DecompressReader): def __init__(self, fp): - super().__init__(_PaddedFile(fp), zlib.decompressobj, + super().__init__(_PaddedFile(fp), zlib._ZlibDecompressor, wbits=-zlib.MAX_WBITS) # Set flag indicating start of a new member self._new_member = True @@ -502,12 +530,13 @@ def read(self, size=-1): self._new_member = False # Read a chunk of data from the file - buf = self._fp.read(io.DEFAULT_BUFFER_SIZE) + if self._decompressor.needs_input: + buf = self._fp.read(READ_BUFFER_SIZE) + uncompress = self._decompressor.decompress(buf, size) + else: + uncompress = self._decompressor.decompress(b"", size) - uncompress = self._decompressor.decompress(buf, size) - if self._decompressor.unconsumed_tail != b"": - self._fp.prepend(self._decompressor.unconsumed_tail) - elif self._decompressor.unused_data != b"": + if self._decompressor.unused_data != b"": # Prepend the already read bytes to the fileobj so they can # be seen by _read_eof() and _read_gzip_header() self._fp.prepend(self._decompressor.unused_data) @@ -518,14 +547,11 @@ def read(self, size=-1): raise EOFError("Compressed file ended before the " "end-of-stream marker was reached") - self._add_read_data( uncompress ) + self._crc = zlib.crc32(uncompress, self._crc) + self._stream_size += len(uncompress) self._pos += len(uncompress) return uncompress - def _add_read_data(self, data): - self._crc = zlib.crc32(data, self._crc) - self._stream_size = self._stream_size + len(data) - def _read_eof(self): # We've read to the end of the file # We check that the computed CRC and size of the @@ -619,13 +645,13 @@ def decompress(data): def main(): from argparse import ArgumentParser parser = ArgumentParser(description= - "A simple command line interface for the gzip module: act like gzip, " - "but do not delete the input file.") + "A simple command line interface for the gzip module: act like gzip, " + "but do not delete the input file.") group = parser.add_mutually_exclusive_group() group.add_argument('--fast', action='store_true', help='compress faster') group.add_argument('--best', action='store_true', help='compress better') group.add_argument("-d", "--decompress", action="store_true", - help="act like gunzip instead of gzip") + help="act like gunzip instead of gzip") parser.add_argument("args", nargs="*", default=["-"], metavar='file') args = parser.parse_args() @@ -655,7 +681,7 @@ def main(): f = builtins.open(arg, "rb") g = open(arg + ".gz", "wb") while True: - chunk = f.read(io.DEFAULT_BUFFER_SIZE) + chunk = f.read(READ_BUFFER_SIZE) if not chunk: break g.write(chunk) diff --git a/Lib/pydoc.py b/Lib/pydoc.py index b521a55047..b1819f91ee 100644 --- a/Lib/pydoc.py +++ b/Lib/pydoc.py @@ -16,12 +16,15 @@ class or function within a module or module in a package. If the Run "pydoc -k " to search for a keyword in the synopsis lines of all available modules. +Run "pydoc -n " to start an HTTP server with the given +hostname (default: localhost) on the local machine. + Run "pydoc -p " to start an HTTP server on the given port on the local machine. Port number 0 can be used to get an arbitrary unused port. Run "pydoc -b" to start an HTTP server on an arbitrary unused port and -open a Web browser to interactively browse documentation. The -p option -can be used with the -b option to explicitly specify the server port. +open a web browser to interactively browse documentation. Combine with +the -n and -p options to control the hostname and port used. Run "pydoc -w " to write out the HTML documentation for a module to a file named ".html". @@ -51,6 +54,7 @@ class or function within a module or module in a package. If the # the current directory is changed with os.chdir(), an incorrect # path will be displayed. +import __future__ import builtins import importlib._bootstrap import importlib._bootstrap_external @@ -63,6 +67,7 @@ class or function within a module or module in a package. If the import platform import re import sys +import sysconfig import time import tokenize import urllib.parse @@ -86,9 +91,101 @@ def pathdirs(): normdirs.append(normdir) return dirs +def _findclass(func): + cls = sys.modules.get(func.__module__) + if cls is None: + return None + for name in func.__qualname__.split('.')[:-1]: + cls = getattr(cls, name) + if not inspect.isclass(cls): + return None + return cls + +def _finddoc(obj): + if inspect.ismethod(obj): + name = obj.__func__.__name__ + self = obj.__self__ + if (inspect.isclass(self) and + getattr(getattr(self, name, None), '__func__') is obj.__func__): + # classmethod + cls = self + else: + cls = self.__class__ + elif inspect.isfunction(obj): + name = obj.__name__ + cls = _findclass(obj) + if cls is None or getattr(cls, name) is not obj: + return None + elif inspect.isbuiltin(obj): + name = obj.__name__ + self = obj.__self__ + if (inspect.isclass(self) and + self.__qualname__ + '.' + name == obj.__qualname__): + # classmethod + cls = self + else: + cls = self.__class__ + # Should be tested before isdatadescriptor(). + elif isinstance(obj, property): + func = obj.fget + name = func.__name__ + cls = _findclass(func) + if cls is None or getattr(cls, name) is not obj: + return None + elif inspect.ismethoddescriptor(obj) or inspect.isdatadescriptor(obj): + name = obj.__name__ + cls = obj.__objclass__ + if getattr(cls, name) is not obj: + return None + if inspect.ismemberdescriptor(obj): + slots = getattr(cls, '__slots__', None) + if isinstance(slots, dict) and name in slots: + return slots[name] + else: + return None + for base in cls.__mro__: + try: + doc = _getowndoc(getattr(base, name)) + except AttributeError: + continue + if doc is not None: + return doc + return None + +def _getowndoc(obj): + """Get the documentation string for an object if it is not + inherited from its class.""" + try: + doc = object.__getattribute__(obj, '__doc__') + if doc is None: + return None + if obj is not type: + typedoc = type(obj).__doc__ + if isinstance(typedoc, str) and typedoc == doc: + return None + return doc + except AttributeError: + return None + +def _getdoc(object): + """Get the documentation string for an object. + + All tabs are expanded to spaces. To clean up docstrings that are + indented to line up with blocks of code, any whitespace than can be + uniformly removed from the second line onwards is removed.""" + doc = _getowndoc(object) + if doc is None: + try: + doc = _finddoc(object) + except (AttributeError, TypeError): + return None + if not isinstance(doc, str): + return None + return inspect.cleandoc(doc) + def getdoc(object): """Get the doc string or comments for an object.""" - result = inspect.getdoc(object) or inspect.getcomments(object) + result = _getdoc(object) or inspect.getcomments(object) return result and re.sub('^ *\n', '', result.rstrip()) or '' def splitdoc(doc): @@ -107,6 +204,19 @@ def classname(object, modname): name = object.__module__ + '.' + name return name +def parentname(object, modname): + """Get a name of the enclosing class (qualified it with a module name + if necessary) or module.""" + if '.' in object.__qualname__: + name = object.__qualname__.rpartition('.')[0] + if object.__module__ != modname: + return object.__module__ + '.' + name + else: + return name + else: + if object.__module__ != modname: + return object.__module__ + def isdata(object): """Check if an object is of a type that probably means it's data.""" return not (inspect.ismodule(object) or inspect.isclass(object) or @@ -134,12 +244,6 @@ def stripid(text): # The behaviour of %p is implementation-dependent in terms of case. return _re_stripid.sub(r'\1', text) -def _is_some_method(obj): - return (inspect.isfunction(obj) or - inspect.ismethod(obj) or - inspect.isbuiltin(obj) or - inspect.ismethoddescriptor(obj)) - def _is_bound_method(fn): """ Returns True if fn is a bound method, regardless of whether @@ -155,7 +259,7 @@ def _is_bound_method(fn): def allmethods(cl): methods = {} - for key, value in inspect.getmembers(cl, _is_some_method): + for key, value in inspect.getmembers(cl, inspect.isroutine): methods[key] = 1 for base in cl.__bases__: methods.update(allmethods(base)) # all your base are belong to us @@ -180,6 +284,8 @@ def _split_list(s, predicate): no.append(x) return yes, no +_future_feature_names = set(__future__.all_feature_names) + def visiblename(name, all=None, obj=None): """Decide whether to show documentation on a variable.""" # Certain special names are redundant or internal. @@ -194,6 +300,10 @@ def visiblename(name, all=None, obj=None): # Namedtuples have public fields and methods with a single leading underscore if name.startswith('_') and hasattr(obj, '_fields'): return True + # Ignore __future__ imports. + if obj is not __future__ and name in _future_feature_names: + if isinstance(getattr(obj, name, None), __future__._Feature): + return False if all is not None: # only document that which the programmer exported in __all__ return name in all @@ -201,11 +311,15 @@ def visiblename(name, all=None, obj=None): return not name.startswith('_') def classify_class_attrs(object): - """Wrap inspect.classify_class_attrs, with fixup for data descriptors.""" + """Wrap inspect.classify_class_attrs, with fixup for data descriptors and bound methods.""" results = [] for (name, kind, cls, value) in inspect.classify_class_attrs(object): if inspect.isdatadescriptor(value): kind = 'data descriptor' + if isinstance(value, property) and value.fset is None: + kind = 'readonly property' + elif kind == 'method' and _is_bound_method(value): + kind = 'static method' results.append((name, kind, cls, value)) return results @@ -290,8 +404,17 @@ def synopsis(filename, cache={}): class ErrorDuringImport(Exception): """Errors that occurred while trying to import something to document it.""" def __init__(self, filename, exc_info): + if not isinstance(exc_info, tuple): + assert isinstance(exc_info, BaseException) + self.exc = type(exc_info) + self.value = exc_info + self.tb = exc_info.__traceback__ + else: + warnings.warn("A tuple value for exc_info is deprecated, use an exception instance", + DeprecationWarning) + + self.exc, self.value, self.tb = exc_info self.filename = filename - self.exc, self.value, self.tb = exc_info def __str__(self): exc = self.exc.__name__ @@ -312,8 +435,8 @@ def importfile(path): spec = importlib.util.spec_from_file_location(name, path, loader=loader) try: return importlib._bootstrap._load(spec) - except: - raise ErrorDuringImport(path, sys.exc_info()) + except BaseException as err: + raise ErrorDuringImport(path, err) def safeimport(path, forceload=0, cache={}): """Import a module; handle errors; return None if the module isn't found. @@ -340,25 +463,21 @@ def safeimport(path, forceload=0, cache={}): # Prevent garbage collection. cache[key] = sys.modules[key] del sys.modules[key] - module = __import__(path) - except: + module = importlib.import_module(path) + except BaseException as err: # Did the error occur before or after the module was found? - (exc, value, tb) = info = sys.exc_info() if path in sys.modules: # An error occurred while executing the imported module. - raise ErrorDuringImport(sys.modules[path].__file__, info) - elif exc is SyntaxError: + raise ErrorDuringImport(sys.modules[path].__file__, err) + elif type(err) is SyntaxError: # A SyntaxError occurred before we could execute the module. - raise ErrorDuringImport(value.filename, info) - elif issubclass(exc, ImportError) and value.name == path: + raise ErrorDuringImport(err.filename, err) + elif isinstance(err, ImportError) and err.name == path: # No such module in the path. return None else: # Some other error occurred during the importing process. - raise ErrorDuringImport(path, sys.exc_info()) - for part in path.split('.')[1:]: - try: module = getattr(module, part) - except AttributeError: return None + raise ErrorDuringImport(path, err) return module # ---------------------------------------------------- formatter base class @@ -376,15 +495,13 @@ def document(self, object, name=None, *args): # identifies something in a way that pydoc itself has issues handling; # think 'super' and how it is a descriptor (which raises the exception # by lacking a __name__ attribute) and an instance. - if inspect.isgetsetdescriptor(object): return self.docdata(*args) - if inspect.ismemberdescriptor(object): return self.docdata(*args) try: if inspect.ismodule(object): return self.docmodule(*args) if inspect.isclass(object): return self.docclass(*args) if inspect.isroutine(object): return self.docroutine(*args) except AttributeError: pass - if isinstance(object, property): return self.docproperty(*args) + if inspect.isdatadescriptor(object): return self.docdata(*args) return self.docother(*args) def fail(self, object, name=None, *args): @@ -395,9 +512,7 @@ def fail(self, object, name=None, *args): docmodule = docclass = docroutine = docother = docproperty = docdata = fail - def getdocloc(self, object, - basedir=os.path.join(sys.base_exec_prefix, "lib", - "python%d.%d" % sys.version_info[:2])): + def getdocloc(self, object, basedir=sysconfig.get_path('stdlib')): """Return the location of module docs or None""" try: @@ -409,14 +524,14 @@ def getdocloc(self, object, basedir = os.path.normcase(basedir) if (isinstance(object, type(os)) and - (object.__name__ in ('errno', 'exceptions', 'gc', 'imp', - 'marshal', 'posix', 'signal', 'sys', - '_thread', 'zipimport') or - (file.startswith(basedir) and - not file.startswith(os.path.join(basedir, 'site-packages')))) and - object.__name__ not in ('xml.etree', 'test.pydoc_mod')): + (object.__name__ in ('errno', 'exceptions', 'gc', + 'marshal', 'posix', 'signal', 'sys', + '_thread', 'zipimport') or + (file.startswith(basedir) and + not file.startswith(os.path.join(basedir, 'site-packages')))) and + object.__name__ not in ('xml.etree', 'test.test_pydoc.pydoc_mod')): if docloc.startswith(("http://", "https://")): - docloc = "%s/%s" % (docloc.rstrip("/"), object.__name__.lower()) + docloc = "{}/{}.html".format(docloc.rstrip("/"), object.__name__.lower()) else: docloc = os.path.join(docloc, object.__name__.lower() + ".html") else: @@ -454,7 +569,7 @@ def repr_string(self, x, level): # needed to make any special characters, so show a raw string. return 'r' + testrepr[0] + self.escape(test) + testrepr[0] return re.sub(r'((\\[\\abfnrtv\'"]|\\[0-9]..|\\x..|\\u....)+)', - r'\1', + r'\1', self.escape(testrepr)) repr_str = repr_string @@ -479,70 +594,69 @@ class HTMLDoc(Doc): def page(self, title, contents): """Format an HTML page.""" return '''\ - -Codestin Search App - - + + + + +Codestin Search App + %s ''' % (title, contents) - def heading(self, title, fgcol, bgcol, extras=''): + def heading(self, title, extras=''): """Format a page heading.""" return ''' - - -
 
- 
%s		%s
- ''' % (bgcol, fgcol, title, fgcol, extras or ' ') - - def section(self, title, fgcol, bgcol, contents, width=6, + + + +
 
%s		%s
+ ''' % (title, extras or ' ') + + def section(self, title, cls, contents, width=6, prelude='', marginalia=None, gap=' '): """Format a section with a heading.""" if marginalia is None: - marginalia = '' + ' ' * width + '' + marginalia = '' + ' ' * width + '' result = '''

- - - - ''' % (bgcol, fgcol, title) +
 
-%s
+ + + ''' % (cls, title) if prelude: result = result + ''' - - -''' % (bgcol, marginalia, prelude, gap) + + +''' % (cls, marginalia, cls, prelude, gap) else: result = result + ''' -''' % (bgcol, marginalia, gap) +''' % (cls, marginalia, gap) - return result + '\n
 
%s
%s%s
%s
%s%s
%s
%s%s
%s%s%s
' % contents + return result + '\n%s' % contents def bigsection(self, title, *args): """Format a section with a big heading.""" - title = '%s' % title + title = '%s' % title return self.section(title, *args) def preformat(self, text): """Format literal preformatted text.""" text = self.escape(text.expandtabs()) return replace(text, '\n\n', '\n \n', '\n\n', '\n \n', - ' ', ' ', '\n', '
\n') + ' ', ' ', '\n', '
\n') - def multicolumn(self, list, format, cols=4): + def multicolumn(self, list, format): """Format a list of items into a multi-column list.""" result = '' - rows = (len(list)+cols-1)//cols - for col in range(cols): - result = result + '' % (100//cols) + rows = (len(list) + 3) // 4 + for col in range(4): + result = result + '' for i in range(rows*col, rows*col+rows): if i < len(list): result = result + format(list[i]) + '
\n' result = result + '' - return '%s
' % result + return '%s
' % result - def grey(self, text): return '%s' % text + def grey(self, text): return '%s' % text def namelink(self, name, *dicts): """Make a link for an identifier, given name-to-URL mappings.""" @@ -559,6 +673,25 @@ def classlink(self, object, modname): module.__name__, name, classname(object, modname)) return classname(object, modname) + def parentlink(self, object, modname): + """Make a link for the enclosing class or module.""" + link = None + name, module = object.__name__, sys.modules.get(object.__module__) + if hasattr(module, name) and getattr(module, name) is object: + if '.' in object.__qualname__: + name = object.__qualname__.rpartition('.')[0] + if object.__module__ != modname: + link = '%s.html#%s' % (module.__name__, name) + else: + link = '#%s' % name + else: + if object.__module__ != modname: + link = '%s.html' % module.__name__ + if link: + return '%s' % (link, parentname(object, modname)) + else: + return parentname(object, modname) + def modulelink(self, object): """Make a link for a module.""" return '%s' % (object.__name__, object.__name__) @@ -588,13 +721,11 @@ def markup(self, text, escape=None, funcs={}, classes={}, methods={}): escape = escape or self.escape results = [] here = 0 - pattern = re.compile(r'\b((http|ftp)://\S+[\w/]|' - r'RFC[- ]?(\d+)|' - r'PEP[- ]?(\d+)|' - r'(self\.)?(\w+))') - while True: - match = pattern.search(text, here) - if not match: break + pattern = re.compile(r'\b((http|https|ftp)://\S+[\w/]|' + r'RFC[- ]?(\d+)|' + r'PEP[- ]?(\d+)|' + r'(self\.)?(\w+))') + while match := pattern.search(text, here): start, end = match.span() results.append(escape(text[here:start])) @@ -603,10 +734,10 @@ def markup(self, text, escape=None, funcs={}, classes={}, methods={}): url = escape(all).replace('"', '"') results.append('%s' % (url, url)) elif rfc: - url = 'http://www.rfc-editor.org/rfc/rfc%d.txt' % int(rfc) + url = 'https://www.rfc-editor.org/rfc/rfc%d.txt' % int(rfc) results.append('%s' % (url, escape(all))) elif pep: - url = 'http://www.python.org/dev/peps/pep-%04d/' % int(pep) + url = 'https://peps.python.org/pep-%04d/' % int(pep) results.append('%s' % (url, escape(all))) elif selfdot: # Create a link for methods like 'self.method(...)' @@ -629,17 +760,17 @@ def formattree(self, tree, modname, parent=None): """Produce HTML for a class tree as given by inspect.getclasstree().""" result = '' for entry in tree: - if type(entry) is type(()): + if isinstance(entry, tuple): c, bases = entry - result = result + '

' + result = result + '
' result = result + self.classlink(c, modname) if bases and bases != (parent,): parents = [] for base in bases: parents.append(self.classlink(base, modname)) result = result + '(' + ', '.join(parents) + ')' - result = result + '\n
' - elif type(entry) is type([]): + result = result + '\n' + elif isinstance(entry, list): result = result + '
\n%s
\n' % self.formattree( entry, modname, c) return '
\n%s
\n' % result @@ -655,10 +786,10 @@ def docmodule(self, object, name=None, mod=None, *ignored): links = [] for i in range(len(parts)-1): links.append( - '%s' % + '%s' % ('.'.join(parts[:i+1]), parts[i])) linkedname = '.'.join(links + parts[-1:]) - head = '%s' % linkedname + head = '%s' % linkedname try: path = inspect.getabsfile(object) url = urllib.parse.quote(path) @@ -680,9 +811,7 @@ def docmodule(self, object, name=None, mod=None, *ignored): docloc = '
Module Reference' % locals() else: docloc = '' - result = self.heading( - head, '#ffffff', '#7799ee', - 'index
' + filelink + docloc) + result = self.heading(head, 'index
' + filelink + docloc) modules = inspect.getmembers(object, inspect.ismodule) @@ -690,7 +819,7 @@ def docmodule(self, object, name=None, mod=None, *ignored): for key, value in inspect.getmembers(object, inspect.isclass): # if __all__ exists, believe it. Otherwise use old heuristic. if (all is not None or - (inspect.getmodule(value) or object) is object): + (inspect.getmodule(value) or object) is object): if visiblename(key, all, object): classes.append((key, value)) cdict[key] = cdict[value] = '#' + key @@ -706,7 +835,7 @@ def docmodule(self, object, name=None, mod=None, *ignored): for key, value in inspect.getmembers(object, inspect.isroutine): # if __all__ exists, believe it. Otherwise use old heuristic. if (all is not None or - inspect.isbuiltin(value) or inspect.getmodule(value) is object): + inspect.isbuiltin(value) or inspect.getmodule(value) is object): if visiblename(key, all, object): funcs.append((key, value)) fdict[key] = '#-' + key @@ -717,7 +846,7 @@ def docmodule(self, object, name=None, mod=None, *ignored): data.append((key, value)) doc = self.markup(getdoc(object), self.preformat, fdict, cdict) - doc = doc and '%s' % doc + doc = doc and '%s' % doc result = result + '

%s

\n' % doc if hasattr(object, '__path__'): @@ -727,12 +856,12 @@ def docmodule(self, object, name=None, mod=None, *ignored): modpkgs.sort() contents = self.multicolumn(modpkgs, self.modpkglink) result = result + self.bigsection( - 'Package Contents', '#ffffff', '#aa55cc', contents) + 'Package Contents', 'pkg-content', contents) elif modules: contents = self.multicolumn( modules, lambda t: self.modulelink(t[1])) result = result + self.bigsection( - 'Modules', '#ffffff', '#aa55cc', contents) + 'Modules', 'pkg-content', contents) if classes: classlist = [value for (key, value) in classes] @@ -741,27 +870,25 @@ def docmodule(self, object, name=None, mod=None, *ignored): for key, value in classes: contents.append(self.document(value, key, name, fdict, cdict)) result = result + self.bigsection( - 'Classes', '#ffffff', '#ee77aa', ' '.join(contents)) + 'Classes', 'index', ' '.join(contents)) if funcs: contents = [] for key, value in funcs: contents.append(self.document(value, key, name, fdict, cdict)) result = result + self.bigsection( - 'Functions', '#ffffff', '#eeaa77', ' '.join(contents)) + 'Functions', 'functions', ' '.join(contents)) if data: contents = [] for key, value in data: contents.append(self.document(value, key)) result = result + self.bigsection( - 'Data', '#ffffff', '#55aa55', '
\n'.join(contents)) + 'Data', 'data', '
\n'.join(contents)) if hasattr(object, '__author__'): contents = self.markup(str(object.__author__), self.preformat) - result = result + self.bigsection( - 'Author', '#ffffff', '#7799ee', contents) + result = result + self.bigsection('Author', 'author', contents) if hasattr(object, '__credits__'): contents = self.markup(str(object.__credits__), self.preformat) - result = result + self.bigsection( - 'Credits', '#ffffff', '#7799ee', contents) + result = result + self.bigsection('Credits', 'credits', contents) return result @@ -806,10 +933,10 @@ def spill(msg, attrs, predicate): except Exception: # Some descriptors may meet a failure in their __get__. # (bug #1785) - push(self._docdescriptor(name, value, mod)) + push(self.docdata(value, name, mod)) else: push(self.document(value, name, mod, - funcs, classes, mdict, object)) + funcs, classes, mdict, object, homecls)) push('\n') return attrs @@ -819,7 +946,7 @@ def spilldescriptors(msg, attrs, predicate): hr.maybe() push(msg) for name, kind, homecls, value in ok: - push(self._docdescriptor(name, value, mod)) + push(self.docdata(value, name, mod)) return attrs def spilldata(msg, attrs, predicate): @@ -829,16 +956,13 @@ def spilldata(msg, attrs, predicate): push(msg) for name, kind, homecls, value in ok: base = self.docother(getattr(object, name), name, mod) - if callable(value) or inspect.isdatadescriptor(value): - doc = getattr(value, "__doc__", None) - else: - doc = None - if doc is None: + doc = getdoc(value) + if not doc: push('
%s
\n' % base) else: doc = self.markup(getdoc(value), self.preformat, funcs, classes, mdict) - doc = '
%s' % doc + doc = '
%s' % doc push('
%s%s
\n' % (base, doc)) push('\n') return attrs @@ -870,7 +994,7 @@ def spilldata(msg, attrs, predicate): thisclass = attrs[0][2] attrs, inherited = _split_list(attrs, lambda t: t[2] is thisclass) - if thisclass is builtins.object: + if object is not builtins.object and thisclass is builtins.object: attrs = inherited continue elif thisclass is object: @@ -889,6 +1013,8 @@ def spilldata(msg, attrs, predicate): lambda t: t[1] == 'class method') attrs = spill('Static methods %s' % tag, attrs, lambda t: t[1] == 'static method') + attrs = spilldescriptors("Readonly properties %s" % tag, attrs, + lambda t: t[1] == 'readonly property') attrs = spilldescriptors('Data descriptors %s' % tag, attrs, lambda t: t[1] == 'data descriptor') attrs = spilldata('Data and other attributes %s' % tag, attrs, @@ -909,42 +1035,85 @@ def spilldata(msg, attrs, predicate): for base in bases: parents.append(self.classlink(base, object.__module__)) title = title + '(%s)' % ', '.join(parents) - doc = self.markup(getdoc(object), self.preformat, funcs, classes, mdict) - doc = doc and '%s
 ' % doc - return self.section(title, '#000000', '#ffc8d8', contents, 3, doc) + decl = '' + try: + signature = inspect.signature(object) + except (ValueError, TypeError): + signature = None + if signature: + argspec = str(signature) + if argspec and argspec != '()': + decl = name + self.escape(argspec) + '\n\n' + + doc = getdoc(object) + if decl: + doc = decl + (doc or '') + doc = self.markup(doc, self.preformat, funcs, classes, mdict) + doc = doc and '%s
 ' % doc + + return self.section(title, 'title', contents, 3, doc) def formatvalue(self, object): """Format an argument default value as text.""" return self.grey('=' + self.repr(object)) def docroutine(self, object, name=None, mod=None, - funcs={}, classes={}, methods={}, cl=None): + funcs={}, classes={}, methods={}, cl=None, homecls=None): """Produce HTML documentation for a function or method object.""" realname = object.__name__ name = name or realname - anchor = (cl and cl.__name__ or '') + '-' + name + if homecls is None: + homecls = cl + anchor = ('' if cl is None else cl.__name__) + '-' + name note = '' - skipdocs = 0 + skipdocs = False + imfunc = None if _is_bound_method(object): - imclass = object.__self__.__class__ - if cl: - if imclass is not cl: - note = ' from ' + self.classlink(imclass, mod) + imself = object.__self__ + if imself is cl: + imfunc = getattr(object, '__func__', None) + elif inspect.isclass(imself): + note = ' class method of %s' % self.classlink(imself, mod) else: - if object.__self__ is not None: - note = ' method of %s instance' % self.classlink( - object.__self__.__class__, mod) - else: - note = ' unbound %s method' % self.classlink(imclass,mod) + note = ' method of %s instance' % self.classlink( + imself.__class__, mod) + elif (inspect.ismethoddescriptor(object) or + inspect.ismethodwrapper(object)): + try: + objclass = object.__objclass__ + except AttributeError: + pass + else: + if cl is None: + note = ' unbound %s method' % self.classlink(objclass, mod) + elif objclass is not homecls: + note = ' from ' + self.classlink(objclass, mod) + else: + imfunc = object + if inspect.isfunction(imfunc) and homecls is not None and ( + imfunc.__module__ != homecls.__module__ or + imfunc.__qualname__ != homecls.__qualname__ + '.' + realname): + pname = self.parentlink(imfunc, mod) + if pname: + note = ' from %s' % pname + + if (inspect.iscoroutinefunction(object) or + inspect.isasyncgenfunction(object)): + asyncqualifier = 'async ' + else: + asyncqualifier = '' if name == realname: title = '%s' % (anchor, realname) else: - if cl and inspect.getattr_static(cl, realname, []) is object: + if (cl is not None and + inspect.getattr_static(cl, realname, []) is object): reallink = '%s' % ( cl.__name__ + '-' + realname, realname) - skipdocs = 1 + skipdocs = True + if note.startswith(' from '): + note = '' else: reallink = realname title = '%s = %s' % ( @@ -962,47 +1131,43 @@ def docroutine(self, object, name=None, mod=None, # XXX lambda's won't usually have func_annotations['return'] # since the syntax doesn't support but it is possible. # So removing parentheses isn't truly safe. - argspec = argspec[1:-1] # remove parentheses + if not object.__annotations__: + argspec = argspec[1:-1] # remove parentheses if not argspec: argspec = '(...)' - decl = title + self.escape(argspec) + (note and self.grey( - '%s' % note)) + decl = asyncqualifier + title + self.escape(argspec) + (note and + self.grey('%s' % note)) if skipdocs: return '
%s
\n' % decl else: doc = self.markup( getdoc(object), self.preformat, funcs, classes, methods) - doc = doc and '
%s
' % doc + doc = doc and '
%s
' % doc return '
%s
%s
\n' % (decl, doc) - def _docdescriptor(self, name, value, mod): + def docdata(self, object, name=None, mod=None, cl=None, *ignored): + """Produce html documentation for a data descriptor.""" results = [] push = results.append if name: push('
%s
\n' % name) - if value.__doc__ is not None: - doc = self.markup(getdoc(value), self.preformat) - push('
%s
\n' % doc) + doc = self.markup(getdoc(object), self.preformat) + if doc: + push('
%s
\n' % doc) push('
\n') return ''.join(results) - def docproperty(self, object, name=None, mod=None, cl=None): - """Produce html documentation for a property.""" - return self._docdescriptor(name, object, mod) + docproperty = docdata def docother(self, object, name=None, mod=None, *ignored): """Produce HTML documentation for a data object.""" lhs = name and '%s = ' % name or '' return lhs + self.repr(object) - def docdata(self, object, name=None, mod=None, cl=None): - """Produce html documentation for a data descriptor.""" - return self._docdescriptor(name, object, mod) - def index(self, dir, shadowed=None): """Generate an HTML index for a directory of modules.""" modpkgs = [] @@ -1016,7 +1181,7 @@ def index(self, dir, shadowed=None): modpkgs.sort() contents = self.multicolumn(modpkgs, self.modpkglink) - return self.bigsection(dir, '#ffffff', '#ee77aa', contents) + return self.bigsection(dir, 'index', contents) # -------------------------------------------- text documentation generator @@ -1067,8 +1232,7 @@ def bold(self, text): def indent(self, text, prefix=' '): """Indent text by prepending a given prefix to each line.""" if not text: return '' - lines = [prefix + line for line in text.split('\n')] - if lines: lines[-1] = lines[-1].rstrip() + lines = [(prefix + line).rstrip() for line in text.split('\n')] return '\n'.join(lines) def section(self, title, contents): @@ -1082,19 +1246,19 @@ def formattree(self, tree, modname, parent=None, prefix=''): """Render in text a class tree as returned by inspect.getclasstree().""" result = '' for entry in tree: - if type(entry) is type(()): + if isinstance(entry, tuple): c, bases = entry result = result + prefix + classname(c, modname) if bases and bases != (parent,): parents = (classname(c, modname) for c in bases) result = result + '(%s)' % ', '.join(parents) result = result + '\n' - elif type(entry) is type([]): + elif isinstance(entry, list): result = result + self.formattree( entry, modname, c, prefix + ' ') return result - def docmodule(self, object, name=None, mod=None): + def docmodule(self, object, name=None, mod=None, *ignored): """Produce text documentation for a given module object.""" name = object.__name__ # ignore the passed-in name synop, desc = splitdoc(getdoc(object)) @@ -1118,14 +1282,14 @@ def docmodule(self, object, name=None, mod=None): for key, value in inspect.getmembers(object, inspect.isclass): # if __all__ exists, believe it. Otherwise use old heuristic. if (all is not None - or (inspect.getmodule(value) or object) is object): + or (inspect.getmodule(value) or object) is object): if visiblename(key, all, object): classes.append((key, value)) funcs = [] for key, value in inspect.getmembers(object, inspect.isroutine): # if __all__ exists, believe it. Otherwise use old heuristic. if (all is not None or - inspect.isbuiltin(value) or inspect.getmodule(value) is object): + inspect.isbuiltin(value) or inspect.getmodule(value) is object): if visiblename(key, all, object): funcs.append((key, value)) data = [] @@ -1212,10 +1376,22 @@ def makename(c, m=object.__module__): parents = map(makename, bases) title = title + '(%s)' % ', '.join(parents) - doc = getdoc(object) - contents = doc and [doc + '\n'] or [] + contents = [] push = contents.append + try: + signature = inspect.signature(object) + except (ValueError, TypeError): + signature = None + if signature: + argspec = str(signature) + if argspec and argspec != '()': + push(name + argspec + '\n') + + doc = getdoc(object) + if doc: + push(doc + '\n') + # List the mro, if non-trivial. mro = deque(inspect.getmro(object)) if len(mro) > 2: @@ -1224,6 +1400,24 @@ def makename(c, m=object.__module__): push(' ' + makename(base)) push('') + # List the built-in subclasses, if any: + subclasses = sorted( + (str(cls.__name__) for cls in type.__subclasses__(object) + if not cls.__name__.startswith("_") and cls.__module__ == "builtins"), + key=str.lower + ) + no_of_subclasses = len(subclasses) + MAX_SUBCLASSES_TO_DISPLAY = 4 + if subclasses: + push("Built-in subclasses:") + for subclassname in subclasses[:MAX_SUBCLASSES_TO_DISPLAY]: + push(' ' + subclassname) + if no_of_subclasses > MAX_SUBCLASSES_TO_DISPLAY: + push(' ... and ' + + str(no_of_subclasses - MAX_SUBCLASSES_TO_DISPLAY) + + ' other subclasses') + push('') + # Cute little class to pump out a horizontal rule between sections. class HorizontalRule: def __init__(self): @@ -1245,10 +1439,10 @@ def spill(msg, attrs, predicate): except Exception: # Some descriptors may meet a failure in their __get__. # (bug #1785) - push(self._docdescriptor(name, value, mod)) + push(self.docdata(value, name, mod)) else: push(self.document(value, - name, mod, object)) + name, mod, object, homecls)) return attrs def spilldescriptors(msg, attrs, predicate): @@ -1257,7 +1451,7 @@ def spilldescriptors(msg, attrs, predicate): hr.maybe() push(msg) for name, kind, homecls, value in ok: - push(self._docdescriptor(name, value, mod)) + push(self.docdata(value, name, mod)) return attrs def spilldata(msg, attrs, predicate): @@ -1266,10 +1460,7 @@ def spilldata(msg, attrs, predicate): hr.maybe() push(msg) for name, kind, homecls, value in ok: - if callable(value) or inspect.isdatadescriptor(value): - doc = getdoc(value) - else: - doc = None + doc = getdoc(value) try: obj = getattr(object, name) except AttributeError: @@ -1289,7 +1480,7 @@ def spilldata(msg, attrs, predicate): thisclass = attrs[0][2] attrs, inherited = _split_list(attrs, lambda t: t[2] is thisclass) - if thisclass is builtins.object: + if object is not builtins.object and thisclass is builtins.object: attrs = inherited continue elif thisclass is object: @@ -1307,6 +1498,8 @@ def spilldata(msg, attrs, predicate): lambda t: t[1] == 'class method') attrs = spill("Static methods %s:\n" % tag, attrs, lambda t: t[1] == 'static method') + attrs = spilldescriptors("Readonly properties %s:\n" % tag, attrs, + lambda t: t[1] == 'readonly property') attrs = spilldescriptors("Data descriptors %s:\n" % tag, attrs, lambda t: t[1] == 'data descriptor') attrs = spilldata("Data and other attributes %s:\n" % tag, attrs, @@ -1324,29 +1517,58 @@ def formatvalue(self, object): """Format an argument default value as text.""" return '=' + self.repr(object) - def docroutine(self, object, name=None, mod=None, cl=None): + def docroutine(self, object, name=None, mod=None, cl=None, homecls=None): """Produce text documentation for a function or method object.""" realname = object.__name__ name = name or realname + if homecls is None: + homecls = cl note = '' - skipdocs = 0 + skipdocs = False + imfunc = None if _is_bound_method(object): - imclass = object.__self__.__class__ - if cl: - if imclass is not cl: - note = ' from ' + classname(imclass, mod) + imself = object.__self__ + if imself is cl: + imfunc = getattr(object, '__func__', None) + elif inspect.isclass(imself): + note = ' class method of %s' % classname(imself, mod) else: - if object.__self__ is not None: - note = ' method of %s instance' % classname( - object.__self__.__class__, mod) - else: - note = ' unbound %s method' % classname(imclass,mod) + note = ' method of %s instance' % classname( + imself.__class__, mod) + elif (inspect.ismethoddescriptor(object) or + inspect.ismethodwrapper(object)): + try: + objclass = object.__objclass__ + except AttributeError: + pass + else: + if cl is None: + note = ' unbound %s method' % classname(objclass, mod) + elif objclass is not homecls: + note = ' from ' + classname(objclass, mod) + else: + imfunc = object + if inspect.isfunction(imfunc) and homecls is not None and ( + imfunc.__module__ != homecls.__module__ or + imfunc.__qualname__ != homecls.__qualname__ + '.' + realname): + pname = parentname(imfunc, mod) + if pname: + note = ' from %s' % pname + + if (inspect.iscoroutinefunction(object) or + inspect.isasyncgenfunction(object)): + asyncqualifier = 'async ' + else: + asyncqualifier = '' if name == realname: title = self.bold(realname) else: - if cl and inspect.getattr_static(cl, realname, []) is object: - skipdocs = 1 + if (cl is not None and + inspect.getattr_static(cl, realname, []) is object): + skipdocs = True + if note.startswith(' from '): + note = '' title = self.bold(name) + ' = ' + realname argspec = None @@ -1362,10 +1584,11 @@ def docroutine(self, object, name=None, mod=None, cl=None): # XXX lambda's won't usually have func_annotations['return'] # since the syntax doesn't support but it is possible. # So removing parentheses isn't truly safe. - argspec = argspec[1:-1] # remove parentheses + if not object.__annotations__: + argspec = argspec[1:-1] # remove parentheses if not argspec: argspec = '(...)' - decl = title + argspec + note + decl = asyncqualifier + title + argspec + note if skipdocs: return decl + '\n' @@ -1373,28 +1596,24 @@ def docroutine(self, object, name=None, mod=None, cl=None): doc = getdoc(object) or '' return decl + '\n' + (doc and self.indent(doc).rstrip() + '\n') - def _docdescriptor(self, name, value, mod): + def docdata(self, object, name=None, mod=None, cl=None, *ignored): + """Produce text documentation for a data descriptor.""" results = [] push = results.append if name: push(self.bold(name)) push('\n') - doc = getdoc(value) or '' + doc = getdoc(object) or '' if doc: push(self.indent(doc)) push('\n') return ''.join(results) - def docproperty(self, object, name=None, mod=None, cl=None): - """Produce text documentation for a property.""" - return self._docdescriptor(name, object, mod) + docproperty = docdata - def docdata(self, object, name=None, mod=None, cl=None): - """Produce text documentation for a data descriptor.""" - return self._docdescriptor(name, object, mod) - - def docother(self, object, name=None, mod=None, parent=None, maxlen=None, doc=None): + def docother(self, object, name=None, mod=None, parent=None, *ignored, + maxlen=None, doc=None): """Produce text documentation for a data object.""" repr = self.repr(object) if maxlen: @@ -1402,8 +1621,10 @@ def docother(self, object, name=None, mod=None, parent=None, maxlen=None, doc=No chop = maxlen - len(line) if chop < 0: repr = repr[:chop] + '...' line = (name and self.bold(name) + ' = ' or '') + repr - if doc is not None: - line += '\n' + self.indent(str(doc)) + if not doc: + doc = getdoc(object) + if doc: + line += '\n' + self.indent(str(doc)) + '\n' return line class _PlainTextDoc(TextDoc): @@ -1427,6 +1648,8 @@ def getpager(): return plainpager if not sys.stdin.isatty() or not sys.stdout.isatty(): return plainpager + if sys.platform == "emscripten": + return plainpager use_pager = os.environ.get('MANPAGER') or os.environ.get('PAGER') if use_pager: if sys.platform == 'win32': # pipes completely broken in Windows @@ -1460,9 +1683,10 @@ def plain(text): def pipepager(text, cmd): """Page through text by feeding it to another program.""" import subprocess - proc = subprocess.Popen(cmd, shell=True, stdin=subprocess.PIPE) + proc = subprocess.Popen(cmd, shell=True, stdin=subprocess.PIPE, + errors='backslashreplace') try: - with io.TextIOWrapper(proc.stdin, errors='backslashreplace') as pipe: + with proc.stdin as pipe: try: pipe.write(text) except KeyboardInterrupt: @@ -1483,13 +1707,14 @@ def pipepager(text, cmd): def tempfilepager(text, cmd): """Page through text by invoking a program on a temporary file.""" import tempfile - filename = tempfile.mktemp() - with open(filename, 'w', errors='backslashreplace') as file: - file.write(text) - try: + with tempfile.TemporaryDirectory() as tempdir: + filename = os.path.join(tempdir, 'pydoc.out') + with open(filename, 'w', errors='backslashreplace', + encoding=os.device_encoding(0) if + sys.platform == 'win32' else None + ) as file: + file.write(text) os.system(cmd + ' "' + filename + '"') - finally: - os.unlink(filename) def _escape_stdout(text): # Escape non-encodable characters to avoid encoding errors later @@ -1611,7 +1836,7 @@ def resolve(thing, forceload=0): return thing, name if isinstance(name, str) else None def render_doc(thing, title='Python Library Documentation: %s', forceload=0, - renderer=None): + renderer=None): """Render text documentation, given an object or a path to an object.""" if renderer is None: renderer = text @@ -1624,38 +1849,43 @@ def render_doc(thing, title='Python Library Documentation: %s', forceload=0, desc += ' in module ' + module.__name__ if not (inspect.ismodule(object) or - inspect.isclass(object) or - inspect.isroutine(object) or - inspect.isgetsetdescriptor(object) or - inspect.ismemberdescriptor(object) or - isinstance(object, property)): + inspect.isclass(object) or + inspect.isroutine(object) or + inspect.isdatadescriptor(object) or + _getdoc(object)): # If the passed object is a piece of data or an instance, # document its available methods instead of its value. - object = type(object) - desc += ' object' + if hasattr(object, '__origin__'): + object = object.__origin__ + else: + object = type(object) + desc += ' object' return title % desc + '\n\n' + renderer.document(object, name) def doc(thing, title='Python Library Documentation: %s', forceload=0, - output=None): + output=None, is_cli=False): """Display text documentation, given an object or a path to an object.""" - try: - if output is None: + if output is None: + try: pager(render_doc(thing, title, forceload)) - else: - output.write(render_doc(thing, title, forceload, plaintext)) - except (ImportError, ErrorDuringImport) as value: - print(value) + except ImportError as exc: + if is_cli: + raise + print(exc) + else: + try: + s = render_doc(thing, title, forceload, plaintext) + except ImportError as exc: + s = str(exc) + output.write(s) def writedoc(thing, forceload=0): """Write HTML documentation to a file in the current directory.""" - try: - object, name = resolve(thing, forceload) - page = html.page(describe(object), html.document(object, name)) - with open(name + '.html', 'w', encoding='utf-8') as file: - file.write(page) - print('wrote', name + '.html') - except (ImportError, ErrorDuringImport) as value: - print(value) + object, name = resolve(thing, forceload) + page = html.page(describe(object), html.document(object, name)) + with open(name + '.html', 'w', encoding='utf-8') as file: + file.write(page) + print('wrote', name + '.html') def writedocs(dir, pkgpath='', done=None): """Write out HTML documentation for all modules in a directory tree.""" @@ -1672,7 +1902,7 @@ class Helper: # in pydoc_data/topics.py. # # CAUTION: if you change one of these dictionaries, be sure to adapt the - # list of needed labels in Doc/tools/pyspecific.py and + # list of needed labels in Doc/tools/extensions/pyspecific.py and # regenerate the pydoc_data/topics.py file by running # make pydoc-topics # in Doc/ and copying the output file into the Lib/ directory. @@ -1684,6 +1914,8 @@ class Helper: 'and': 'BOOLEAN', 'as': 'with', 'assert': ('assert', ''), + 'async': ('async', ''), + 'await': ('await', ''), 'break': ('break', 'while for'), 'class': ('class', 'CLASSES SPECIALMETHODS'), 'continue': ('continue', 'while for'), @@ -1722,7 +1954,7 @@ class Helper: 'COMPARISON' : ('<', '>', '<=', '>=', '==', '!=', '<>'), 'UNARY' : ('-', '~'), 'AUGMENTEDASSIGNMENT' : ('+=', '-=', '*=', '/=', '%=', '&=', '|=', - '^=', '<<=', '>>=', '**=', '//='), + '^=', '<<=', '>>=', '**=', '//='), 'BITWISE' : ('<<', '>>', '&', '|', '^', '~'), 'COMPLEX' : ('j', 'J') } @@ -1749,16 +1981,17 @@ class Helper: if topic not in topics: topics = topics + ' ' + topic symbols[symbol] = topics + del topic, symbols_, symbol, topics topics = { 'TYPES': ('types', 'STRINGS UNICODE NUMBERS SEQUENCES MAPPINGS ' - 'FUNCTIONS CLASSES MODULES FILES inspect'), + 'FUNCTIONS CLASSES MODULES FILES inspect'), 'STRINGS': ('strings', 'str UNICODE SEQUENCES STRINGMETHODS ' - 'FORMATTING TYPES'), + 'FORMATTING TYPES'), 'STRINGMETHODS': ('string-methods', 'STRINGS FORMATTING'), 'FORMATTING': ('formatstrings', 'OPERATORS'), 'UNICODE': ('strings', 'encodings unicode SEQUENCES STRINGMETHODS ' - 'FORMATTING TYPES'), + 'FORMATTING TYPES'), 'NUMBERS': ('numbers', 'INTEGER FLOAT COMPLEX TYPES'), 'INTEGER': ('integers', 'int range'), 'FLOAT': ('floating', 'float math'), @@ -1778,23 +2011,23 @@ class Helper: 'MODULES': ('typesmodules', 'import'), 'PACKAGES': 'import', 'EXPRESSIONS': ('operator-summary', 'lambda or and not in is BOOLEAN ' - 'COMPARISON BITWISE SHIFTING BINARY FORMATTING POWER ' - 'UNARY ATTRIBUTES SUBSCRIPTS SLICINGS CALLS TUPLES ' - 'LISTS DICTIONARIES'), + 'COMPARISON BITWISE SHIFTING BINARY FORMATTING POWER ' + 'UNARY ATTRIBUTES SUBSCRIPTS SLICINGS CALLS TUPLES ' + 'LISTS DICTIONARIES'), 'OPERATORS': 'EXPRESSIONS', 'PRECEDENCE': 'EXPRESSIONS', 'OBJECTS': ('objects', 'TYPES'), 'SPECIALMETHODS': ('specialnames', 'BASICMETHODS ATTRIBUTEMETHODS ' - 'CALLABLEMETHODS SEQUENCEMETHODS MAPPINGMETHODS ' - 'NUMBERMETHODS CLASSES'), + 'CALLABLEMETHODS SEQUENCEMETHODS MAPPINGMETHODS ' + 'NUMBERMETHODS CLASSES'), 'BASICMETHODS': ('customization', 'hash repr str SPECIALMETHODS'), 'ATTRIBUTEMETHODS': ('attribute-access', 'ATTRIBUTES SPECIALMETHODS'), 'CALLABLEMETHODS': ('callable-types', 'CALLS SPECIALMETHODS'), 'SEQUENCEMETHODS': ('sequence-types', 'SEQUENCES SEQUENCEMETHODS ' - 'SPECIALMETHODS'), + 'SPECIALMETHODS'), 'MAPPINGMETHODS': ('sequence-types', 'MAPPINGS SPECIALMETHODS'), 'NUMBERMETHODS': ('numeric-types', 'NUMBERS AUGMENTEDASSIGNMENT ' - 'SPECIALMETHODS'), + 'SPECIALMETHODS'), 'EXECUTION': ('execmodel', 'NAMESPACES DYNAMICFEATURES EXCEPTIONS'), 'NAMESPACES': ('naming', 'global nonlocal ASSIGNMENT DELETION DYNAMICFEATURES'), 'DYNAMICFEATURES': ('dynamic-features', ''), @@ -1806,7 +2039,7 @@ class Helper: 'SPECIALIDENTIFIERS': ('id-classes', ''), 'PRIVATENAMES': ('atom-identifiers', ''), 'LITERALS': ('atom-literals', 'STRINGS NUMBERS TUPLELITERALS ' - 'LISTLITERALS DICTIONARYLITERALS'), + 'LISTLITERALS DICTIONARYLITERALS'), 'TUPLES': 'SEQUENCES', 'TUPLELITERALS': ('exprlists', 'TUPLES LITERALS'), 'LISTS': ('typesseq-mutable', 'LISTLITERALS'), @@ -1841,8 +2074,13 @@ def __init__(self, input=None, output=None): self._input = input self._output = output - input = property(lambda self: self._input or sys.stdin) - output = property(lambda self: self._output or sys.stdout) + @property + def input(self): + return self._input or sys.stdin + + @property + def output(self): + return self._output or sys.stdout def __repr__(self): if inspect.stack()[1][3] == '?': @@ -1854,7 +2092,10 @@ def __repr__(self): _GoInteractive = object() def __call__(self, request=_GoInteractive): if request is not self._GoInteractive: - self.help(request) + try: + self.help(request) + except ImportError as err: + self.output.write(f'{err}\n') else: self.intro() self.interact() @@ -1895,8 +2136,8 @@ def getline(self, prompt): self.output.flush() return self.input.readline() - def help(self, request): - if type(request) is type(''): + def help(self, request, is_cli=False): + if isinstance(request, str): request = request.strip() if request == 'keywords': self.listkeywords() elif request == 'symbols': self.listsymbols() @@ -1907,30 +2148,32 @@ def help(self, request): elif request in self.symbols: self.showsymbol(request) elif request in ['True', 'False', 'None']: # special case these keywords since they are objects too - doc(eval(request), 'Help on %s:') + doc(eval(request), 'Help on %s:', output=self._output, is_cli=is_cli) elif request in self.keywords: self.showtopic(request) elif request in self.topics: self.showtopic(request) - elif request: doc(request, 'Help on %s:', output=self._output) - else: doc(str, 'Help on %s:', output=self._output) + elif request: doc(request, 'Help on %s:', output=self._output, is_cli=is_cli) + else: doc(str, 'Help on %s:', output=self._output, is_cli=is_cli) elif isinstance(request, Helper): self() - else: doc(request, 'Help on %s:', output=self._output) + else: doc(request, 'Help on %s:', output=self._output, is_cli=is_cli) self.output.write('\n') def intro(self): - self.output.write(''' -Welcome to Python {0}'s help utility! - -If this is your first time using Python, you should definitely check out -the tutorial on the Internet at https://docs.python.org/{0}/tutorial/. + self.output.write('''\ +Welcome to Python {0}'s help utility! If this is your first time using +Python, you should definitely check out the tutorial at +https://docs.python.org/{0}/tutorial/. Enter the name of any module, keyword, or topic to get help on writing -Python programs and using Python modules. To quit this help utility and -return to the interpreter, just type "quit". +Python programs and using Python modules. To get a list of available +modules, keywords, symbols, or topics, enter "modules", "keywords", +"symbols", or "topics". + +Each module also comes with a one-line summary of what it does; to list +the modules whose name or summary contain a given string such as "spam", +enter "modules spam". -To get a list of available modules, keywords, symbols, or topics, type -"modules", "keywords", "symbols", or "topics". Each module also comes -with a one-line summary of what it does; to list the modules whose name -or summary contain a given string such as "spam", type "modules spam". +To quit this help utility and return to the interpreter, +enter "q" or "quit". '''.format('%d.%d' % sys.version_info[:2])) def list(self, items, columns=4, width=80): @@ -1981,7 +2224,7 @@ def showtopic(self, topic, more_xrefs=''): if not target: self.output.write('no documentation found for %s\n' % repr(topic)) return - if type(target) is type(''): + if isinstance(target, str): return self.showtopic(target, more_xrefs) label, xrefs = target @@ -1998,7 +2241,11 @@ def showtopic(self, topic, more_xrefs=''): text = 'Related help topics: ' + ', '.join(xrefs.split()) + '\n' wrapped_text = textwrap.wrap(text, 72) doc += '\n%s\n' % '\n'.join(wrapped_text) - pager(doc) + + if self._output is None: + pager(doc) + else: + self.output.write(doc) def _gettopic(self, topic, more_xrefs=''): """Return unbuffered tuple of (topic, xrefs). @@ -2090,7 +2337,7 @@ def run(self, callback, key=None, completer=None, onerror=None): callback(None, modname, '') else: try: - spec = pkgutil._get_spec(importer, modname) + spec = importer.find_spec(modname) except SyntaxError: # raised by tests for bad coding cookies or BOM continue @@ -2135,13 +2382,13 @@ def onerror(modname): warnings.filterwarnings('ignore') # ignore problems during import ModuleScanner().run(callback, key, onerror=onerror) -# --------------------------------------- enhanced Web browser interface +# --------------------------------------- enhanced web browser interface -def _start_server(urlhandler, port): +def _start_server(urlhandler, hostname, port): """Start an HTTP server thread on a specific port. Start an HTML/text server thread, so HTML or text documents can be - browsed dynamically and interactively with a Web browser. Example use: + browsed dynamically and interactively with a web browser. Example use: >>> import time >>> import pydoc @@ -2177,14 +2424,14 @@ def _start_server(urlhandler, port): Let the server do its thing. We just need to monitor its status. Use time.sleep so the loop doesn't hog the CPU. - >>> starttime = time.time() + >>> starttime = time.monotonic() >>> timeout = 1 #seconds This is a short timeout for testing purposes. >>> while serverthread.serving: ... time.sleep(.01) - ... if serverthread.serving and time.time() - starttime > timeout: + ... if serverthread.serving and time.monotonic() - starttime > timeout: ... serverthread.stop() ... break @@ -2222,8 +2469,8 @@ def log_message(self, *args): class DocServer(http.server.HTTPServer): - def __init__(self, port, callback): - self.host = 'localhost' + def __init__(self, host, port, callback): + self.host = host self.address = (self.host, port) self.callback = callback self.base.__init__(self, self.address, self.handler) @@ -2243,12 +2490,14 @@ def server_activate(self): class ServerThread(threading.Thread): - def __init__(self, urlhandler, port): + def __init__(self, urlhandler, host, port): self.urlhandler = urlhandler + self.host = host self.port = int(port) threading.Thread.__init__(self) self.serving = False self.error = None + self.docserver = None def run(self): """Start the server.""" @@ -2257,11 +2506,11 @@ def run(self): DocServer.handler = DocHandler DocHandler.MessageClass = email.message.Message DocHandler.urlhandler = staticmethod(self.urlhandler) - docsvr = DocServer(self.port, self.ready) + docsvr = DocServer(self.host, self.port, self.ready) self.docserver = docsvr docsvr.serve_until_quit() - except Exception as e: - self.error = e + except Exception as err: + self.error = err def ready(self, server): self.serving = True @@ -2279,11 +2528,11 @@ def stop(self): self.serving = False self.url = None - thread = ServerThread(urlhandler, port) + thread = ServerThread(urlhandler, hostname, port) thread.start() - # Wait until thread.serving is True to make sure we are - # really up before returning. - while not thread.error and not thread.serving: + # Wait until thread.serving is True and thread.docserver is set + # to make sure we are really up before returning. + while not thread.error and not (thread.serving and thread.docserver): time.sleep(.01) return thread @@ -2303,18 +2552,17 @@ def page(self, title, contents): """Format an HTML page.""" css_path = "pydoc_data/_pydoc.css" css_link = ( - '' % - css_path) + '' % + css_path) return '''\ - -Codestin Search App - -%s%s
%s
+ + + + +Codestin Search App +%s%s
%s
''' % (title, css_link, html_navbar(), contents) - def filelink(self, url, path): - return '%s' % (url, path) - html = _HTMLDoc() @@ -2352,22 +2600,21 @@ def bltinlink(name): return '%s' % (name, name) heading = html.heading( - 'Index of Modules', - '#ffffff', '#7799ee') + 'Index of Modules' + ) names = [name for name in sys.builtin_module_names if name != '__main__'] contents = html.multicolumn(names, bltinlink) contents = [heading, '

' + html.bigsection( - 'Built-in Modules', '#ffffff', '#ee77aa', contents)] + 'Built-in Modules', 'index', contents)] seen = {} for dir in sys.path: contents.append(html.index(dir, seen)) contents.append( - '

pydoc by Ka-Ping Yee' - '<ping@lfw.org>') + '

pydoc by Ka-Ping Yee' + '<ping@lfw.org>

') return 'Index of Modules', ''.join(contents) def html_search(key): @@ -2392,27 +2639,14 @@ def bltinlink(name): results = [] heading = html.heading( - 'Search Results', - '#ffffff', '#7799ee') + 'Search Results', + ) for name, desc in search_result: results.append(bltinlink(name) + desc) contents = heading + html.bigsection( - 'key = %s' % key, '#ffffff', '#ee77aa', '
'.join(results)) + 'key = %s' % key, 'index', '
'.join(results)) return 'Search Results', contents - def html_getfile(path): - """Get and display a source file listing safely.""" - path = urllib.parse.unquote(path) - with tokenize.open(path) as fp: - lines = html.escape(fp.read()) - body = '
%s
' % lines - heading = html.heading( - 'File Listing', - '#ffffff', '#7799ee') - contents = heading + html.bigsection( - 'File: %s' % path, '#ffffff', '#ee77aa', body) - return 'getfile %s' % path, contents - def html_topics(): """Index of topic texts available.""" @@ -2420,20 +2654,20 @@ def bltinlink(name): return '%s' % (name, name) heading = html.heading( - 'INDEX', - '#ffffff', '#7799ee') + 'INDEX', + ) names = sorted(Helper.topics.keys()) contents = html.multicolumn(names, bltinlink) contents = heading + html.bigsection( - 'Topics', '#ffffff', '#ee77aa', contents) + 'Topics', 'index', contents) return 'Topics', contents def html_keywords(): """Index of keywords.""" heading = html.heading( - 'INDEX', - '#ffffff', '#7799ee') + 'INDEX', + ) names = sorted(Helper.keywords.keys()) def bltinlink(name): @@ -2441,7 +2675,7 @@ def bltinlink(name): contents = html.multicolumn(names, bltinlink) contents = heading + html.bigsection( - 'Keywords', '#ffffff', '#ee77aa', contents) + 'Keywords', 'index', contents) return 'Keywords', contents def html_topicpage(topic): @@ -2454,10 +2688,10 @@ def html_topicpage(topic): else: title = 'TOPIC' heading = html.heading( - '%s' % title, - '#ffffff', '#7799ee') + '%s' % title, + ) contents = '
%s
' % html.markup(contents) - contents = html.bigsection(topic , '#ffffff','#ee77aa', contents) + contents = html.bigsection(topic , 'index', contents) if xrefs: xrefs = sorted(xrefs.split()) @@ -2465,8 +2699,7 @@ def bltinlink(name): return '%s' % (name, name) xrefs = html.multicolumn(xrefs, bltinlink) - xrefs = html.section('Related help topics: ', - '#ffffff', '#ee77aa', xrefs) + xrefs = html.section('Related help topics: ', 'index', xrefs) return ('%s %s' % (title, topic), ''.join((heading, contents, xrefs))) @@ -2480,12 +2713,11 @@ def html_getobj(url): def html_error(url, exc): heading = html.heading( - 'Error', - '#ffffff', '#7799ee') + 'Error', + ) contents = '
'.join(html.escape(line) for line in format_exception_only(type(exc), exc)) - contents = heading + html.bigsection(url, '#ffffff', '#bb0000', - contents) + contents = heading + html.bigsection(url, 'error', contents) return "Error - %s" % url, contents def get_html_page(url): @@ -2504,8 +2736,6 @@ def get_html_page(url): op, _, url = url.partition('=') if op == "search?key": title, content = html_search(url) - elif op == "getfile?key": - title, content = html_getfile(url) elif op == "topic?key": # try topics first, then objects. try: @@ -2543,14 +2773,14 @@ def get_html_page(url): raise TypeError('unknown content type %r for url %s' % (content_type, url)) -def browse(port=0, *, open_browser=True): - """Start the enhanced pydoc Web server and open a Web browser. +def browse(port=0, *, open_browser=True, hostname='localhost'): + """Start the enhanced pydoc web server and open a web browser. Use port '0' to start the server on an arbitrary port. Set open_browser to False to suppress opening a browser. """ import webbrowser - serverthread = _start_server(_url_handler, port) + serverthread = _start_server(_url_handler, hostname, port) if serverthread.error: print(serverthread.error) return @@ -2583,25 +2813,58 @@ def browse(port=0, *, open_browser=True): def ispath(x): return isinstance(x, str) and x.find(os.sep) >= 0 +def _get_revised_path(given_path, argv0): + """Ensures current directory is on returned path, and argv0 directory is not + + Exception: argv0 dir is left alone if it's also pydoc's directory. + + Returns a new path entry list, or None if no adjustment is needed. + """ + # Scripts may get the current directory in their path by default if they're + # run with the -m switch, or directly from the current directory. + # The interactive prompt also allows imports from the current directory. + + # Accordingly, if the current directory is already present, don't make + # any changes to the given_path + if '' in given_path or os.curdir in given_path or os.getcwd() in given_path: + return None + + # Otherwise, add the current directory to the given path, and remove the + # script directory (as long as the latter isn't also pydoc's directory. + stdlib_dir = os.path.dirname(__file__) + script_dir = os.path.dirname(argv0) + revised_path = given_path.copy() + if script_dir in given_path and not os.path.samefile(script_dir, stdlib_dir): + revised_path.remove(script_dir) + revised_path.insert(0, os.getcwd()) + return revised_path + + +# Note: the tests only cover _get_revised_path, not _adjust_cli_path itself +def _adjust_cli_sys_path(): + """Ensures current directory is on sys.path, and __main__ directory is not. + + Exception: __main__ dir is left alone if it's also pydoc's directory. + """ + revised_path = _get_revised_path(sys.path, sys.argv[0]) + if revised_path is not None: + sys.path[:] = revised_path + + def cli(): """Command-line interface (looks at sys.argv to decide what to do).""" import getopt class BadUsage(Exception): pass - # Scripts don't get the current directory in their path by default - # unless they are run with the '-m' switch - if '' not in sys.path: - scriptdir = os.path.dirname(sys.argv[0]) - if scriptdir in sys.path: - sys.path.remove(scriptdir) - sys.path.insert(0, '.') + _adjust_cli_sys_path() try: - opts, args = getopt.getopt(sys.argv[1:], 'bk:p:w') + opts, args = getopt.getopt(sys.argv[1:], 'bk:n:p:w') writing = False start_server = False open_browser = False - port = None + port = 0 + hostname = 'localhost' for opt, val in opts: if opt == '-b': start_server = True @@ -2614,18 +2877,19 @@ class BadUsage(Exception): pass port = val if opt == '-w': writing = True + if opt == '-n': + start_server = True + hostname = val if start_server: - if port is None: - port = 0 - browse(port, open_browser=open_browser) + browse(port, hostname=hostname, open_browser=open_browser) return if not args: raise BadUsage for arg in args: if ispath(arg) and not os.path.exists(arg): print('file %r does not exist' % arg) - break + sys.exit(1) try: if ispath(arg) and os.path.isfile(arg): arg = importfile(arg) @@ -2635,9 +2899,10 @@ class BadUsage(Exception): pass else: writedoc(arg) else: - help.help(arg) - except ErrorDuringImport as value: + help.help(arg, is_cli=True) + except (ImportError, ErrorDuringImport) as value: print(value) + sys.exit(1) except (getopt.error, BadUsage): cmd = os.path.splitext(os.path.basename(sys.argv[0]))[0] @@ -2654,14 +2919,17 @@ class BadUsage(Exception): pass {cmd} -k Search for a keyword in the synopsis lines of all available modules. +{cmd} -n + Start an HTTP server with the given hostname (default: localhost). + {cmd} -p Start an HTTP server on the given port on the local machine. Port number 0 can be used to get an arbitrary unused port. {cmd} -b - Start an HTTP server on an arbitrary unused port and open a Web browser - to interactively browse documentation. The -p option can be used with - the -b option to explicitly specify the server port. + Start an HTTP server on an arbitrary unused port and open a web browser + to interactively browse documentation. This option can be used in + combination with -n and/or -p. {cmd} -w ... Write out the HTML documentation for a module to a file in the current diff --git a/Lib/pydoc_data/topics.py b/Lib/pydoc_data/topics.py index e4c6305808..f735c7c5c4 100644 --- a/Lib/pydoc_data/topics.py +++ b/Lib/pydoc_data/topics.py @@ -1,13062 +1,17051 @@ # -*- coding: utf-8 -*- -# Autogenerated by Sphinx on Sun Dec 23 16:24:21 2018 +# Autogenerated by Sphinx on Tue Dec 3 19:41:14 2024 +# as part of the release process. topics = {'assert': 'The "assert" statement\n' - '**********************\n' - '\n' - 'Assert statements are a convenient way to insert debugging ' - 'assertions\n' - 'into a program:\n' - '\n' - ' assert_stmt ::= "assert" expression ["," expression]\n' - '\n' - 'The simple form, "assert expression", is equivalent to\n' - '\n' - ' if __debug__:\n' - ' if not expression: raise AssertionError\n' - '\n' - 'The extended form, "assert expression1, expression2", is ' - 'equivalent to\n' - '\n' - ' if __debug__:\n' - ' if not expression1: raise AssertionError(expression2)\n' - '\n' - 'These equivalences assume that "__debug__" and "AssertionError" ' - 'refer\n' - 'to the built-in variables with those names. In the current\n' - 'implementation, the built-in variable "__debug__" is "True" under\n' - 'normal circumstances, "False" when optimization is requested ' - '(command\n' - 'line option "-O"). The current code generator emits no code for ' - 'an\n' - 'assert statement when optimization is requested at compile time. ' - 'Note\n' - 'that it is unnecessary to include the source code for the ' - 'expression\n' - 'that failed in the error message; it will be displayed as part of ' - 'the\n' - 'stack trace.\n' - '\n' - 'Assignments to "__debug__" are illegal. The value for the ' - 'built-in\n' - 'variable is determined when the interpreter starts.\n', - 'assignment': 'Assignment statements\n' - '*********************\n' - '\n' - 'Assignment statements are used to (re)bind names to values and ' - 'to\n' - 'modify attributes or items of mutable objects:\n' - '\n' - ' assignment_stmt ::= (target_list "=")+ (starred_expression ' - '| yield_expression)\n' - ' target_list ::= target ("," target)* [","]\n' - ' target ::= identifier\n' - ' | "(" [target_list] ")"\n' - ' | "[" [target_list] "]"\n' - ' | attributeref\n' - ' | subscription\n' - ' | slicing\n' - ' | "*" target\n' - '\n' - '(See section Primaries for the syntax definitions for ' - '*attributeref*,\n' - '*subscription*, and *slicing*.)\n' - '\n' - 'An assignment statement evaluates the expression list ' - '(remember that\n' - 'this can be a single expression or a comma-separated list, the ' - 'latter\n' - 'yielding a tuple) and assigns the single resulting object to ' - 'each of\n' - 'the target lists, from left to right.\n' - '\n' - 'Assignment is defined recursively depending on the form of the ' - 'target\n' - '(list). When a target is part of a mutable object (an ' - 'attribute\n' - 'reference, subscription or slicing), the mutable object must\n' - 'ultimately perform the assignment and decide about its ' - 'validity, and\n' - 'may raise an exception if the assignment is unacceptable. The ' - 'rules\n' - 'observed by various types and the exceptions raised are given ' - 'with the\n' - 'definition of the object types (see section The standard type\n' - 'hierarchy).\n' - '\n' - 'Assignment of an object to a target list, optionally enclosed ' - 'in\n' - 'parentheses or square brackets, is recursively defined as ' - 'follows.\n' - '\n' - '* If the target list is a single target with no trailing ' - 'comma,\n' - ' optionally in parentheses, the object is assigned to that ' - 'target.\n' - '\n' - '* Else: The object must be an iterable with the same number of ' - 'items\n' - ' as there are targets in the target list, and the items are ' - 'assigned,\n' - ' from left to right, to the corresponding targets.\n' - '\n' - ' * If the target list contains one target prefixed with an\n' - ' asterisk, called a “starred” target: The object must be ' - 'an\n' - ' iterable with at least as many items as there are targets ' - 'in the\n' - ' target list, minus one. The first items of the iterable ' - 'are\n' - ' assigned, from left to right, to the targets before the ' - 'starred\n' - ' target. The final items of the iterable are assigned to ' - 'the\n' - ' targets after the starred target. A list of the remaining ' - 'items\n' - ' in the iterable is then assigned to the starred target ' - '(the list\n' - ' can be empty).\n' - '\n' - ' * Else: The object must be an iterable with the same number ' - 'of\n' - ' items as there are targets in the target list, and the ' - 'items are\n' - ' assigned, from left to right, to the corresponding ' - 'targets.\n' - '\n' - 'Assignment of an object to a single target is recursively ' - 'defined as\n' - 'follows.\n' - '\n' - '* If the target is an identifier (name):\n' - '\n' - ' * If the name does not occur in a "global" or "nonlocal" ' - 'statement\n' - ' in the current code block: the name is bound to the object ' - 'in the\n' - ' current local namespace.\n' - '\n' - ' * Otherwise: the name is bound to the object in the global\n' - ' namespace or the outer namespace determined by ' - '"nonlocal",\n' - ' respectively.\n' - '\n' - ' The name is rebound if it was already bound. This may cause ' - 'the\n' - ' reference count for the object previously bound to the name ' - 'to reach\n' - ' zero, causing the object to be deallocated and its ' - 'destructor (if it\n' - ' has one) to be called.\n' - '\n' - '* If the target is an attribute reference: The primary ' - 'expression in\n' - ' the reference is evaluated. It should yield an object with\n' - ' assignable attributes; if this is not the case, "TypeError" ' - 'is\n' - ' raised. That object is then asked to assign the assigned ' - 'object to\n' - ' the given attribute; if it cannot perform the assignment, it ' - 'raises\n' - ' an exception (usually but not necessarily ' - '"AttributeError").\n' - '\n' - ' Note: If the object is a class instance and the attribute ' - 'reference\n' - ' occurs on both sides of the assignment operator, the RHS ' - 'expression,\n' - ' "a.x" can access either an instance attribute or (if no ' - 'instance\n' - ' attribute exists) a class attribute. The LHS target "a.x" ' - 'is always\n' - ' set as an instance attribute, creating it if necessary. ' - 'Thus, the\n' - ' two occurrences of "a.x" do not necessarily refer to the ' - 'same\n' - ' attribute: if the RHS expression refers to a class ' - 'attribute, the\n' - ' LHS creates a new instance attribute as the target of the\n' - ' assignment:\n' - '\n' - ' class Cls:\n' - ' x = 3 # class variable\n' - ' inst = Cls()\n' - ' inst.x = inst.x + 1 # writes inst.x as 4 leaving Cls.x ' - 'as 3\n' - '\n' - ' This description does not necessarily apply to descriptor\n' - ' attributes, such as properties created with "property()".\n' - '\n' - '* If the target is a subscription: The primary expression in ' - 'the\n' - ' reference is evaluated. It should yield either a mutable ' - 'sequence\n' - ' object (such as a list) or a mapping object (such as a ' - 'dictionary).\n' - ' Next, the subscript expression is evaluated.\n' - '\n' - ' If the primary is a mutable sequence object (such as a ' - 'list), the\n' - ' subscript must yield an integer. If it is negative, the ' - 'sequence’s\n' - ' length is added to it. The resulting value must be a ' - 'nonnegative\n' - ' integer less than the sequence’s length, and the sequence is ' - 'asked\n' - ' to assign the assigned object to its item with that index. ' - 'If the\n' - ' index is out of range, "IndexError" is raised (assignment to ' - 'a\n' - ' subscripted sequence cannot add new items to a list).\n' - '\n' - ' If the primary is a mapping object (such as a dictionary), ' - 'the\n' - ' subscript must have a type compatible with the mapping’s key ' - 'type,\n' - ' and the mapping is then asked to create a key/datum pair ' - 'which maps\n' - ' the subscript to the assigned object. This can either ' - 'replace an\n' - ' existing key/value pair with the same key value, or insert a ' - 'new\n' - ' key/value pair (if no key with the same value existed).\n' - '\n' - ' For user-defined objects, the "__setitem__()" method is ' - 'called with\n' - ' appropriate arguments.\n' - '\n' - '* If the target is a slicing: The primary expression in the\n' - ' reference is evaluated. It should yield a mutable sequence ' - 'object\n' - ' (such as a list). The assigned object should be a sequence ' - 'object\n' - ' of the same type. Next, the lower and upper bound ' - 'expressions are\n' - ' evaluated, insofar they are present; defaults are zero and ' - 'the\n' - ' sequence’s length. The bounds should evaluate to integers. ' - 'If\n' - ' either bound is negative, the sequence’s length is added to ' - 'it. The\n' - ' resulting bounds are clipped to lie between zero and the ' - 'sequence’s\n' - ' length, inclusive. Finally, the sequence object is asked to ' - 'replace\n' - ' the slice with the items of the assigned sequence. The ' - 'length of\n' - ' the slice may be different from the length of the assigned ' - 'sequence,\n' - ' thus changing the length of the target sequence, if the ' - 'target\n' - ' sequence allows it.\n' - '\n' - '**CPython implementation detail:** In the current ' - 'implementation, the\n' - 'syntax for targets is taken to be the same as for expressions, ' - 'and\n' - 'invalid syntax is rejected during the code generation phase, ' - 'causing\n' - 'less detailed error messages.\n' - '\n' - 'Although the definition of assignment implies that overlaps ' - 'between\n' - 'the left-hand side and the right-hand side are ‘simultaneous’ ' - '(for\n' - 'example "a, b = b, a" swaps two variables), overlaps *within* ' - 'the\n' - 'collection of assigned-to variables occur left-to-right, ' - 'sometimes\n' - 'resulting in confusion. For instance, the following program ' - 'prints\n' - '"[0, 2]":\n' - '\n' - ' x = [0, 1]\n' - ' i = 0\n' - ' i, x[i] = 1, 2 # i is updated, then x[i] is ' - 'updated\n' - ' print(x)\n' - '\n' - 'See also:\n' - '\n' - ' **PEP 3132** - Extended Iterable Unpacking\n' - ' The specification for the "*target" feature.\n' - '\n' - '\n' - 'Augmented assignment statements\n' - '===============================\n' - '\n' - 'Augmented assignment is the combination, in a single ' - 'statement, of a\n' - 'binary operation and an assignment statement:\n' - '\n' - ' augmented_assignment_stmt ::= augtarget augop ' - '(expression_list | yield_expression)\n' - ' augtarget ::= identifier | attributeref | ' - 'subscription | slicing\n' - ' augop ::= "+=" | "-=" | "*=" | "@=" | ' - '"/=" | "//=" | "%=" | "**="\n' - ' | ">>=" | "<<=" | "&=" | "^=" | "|="\n' - '\n' - '(See section Primaries for the syntax definitions of the last ' - 'three\n' - 'symbols.)\n' - '\n' - 'An augmented assignment evaluates the target (which, unlike ' - 'normal\n' - 'assignment statements, cannot be an unpacking) and the ' - 'expression\n' - 'list, performs the binary operation specific to the type of ' - 'assignment\n' - 'on the two operands, and assigns the result to the original ' - 'target.\n' - 'The target is only evaluated once.\n' - '\n' - 'An augmented assignment expression like "x += 1" can be ' - 'rewritten as\n' - '"x = x + 1" to achieve a similar, but not exactly equal ' - 'effect. In the\n' - 'augmented version, "x" is only evaluated once. Also, when ' - 'possible,\n' - 'the actual operation is performed *in-place*, meaning that ' - 'rather than\n' - 'creating a new object and assigning that to the target, the ' - 'old object\n' - 'is modified instead.\n' - '\n' - 'Unlike normal assignments, augmented assignments evaluate the ' - 'left-\n' - 'hand side *before* evaluating the right-hand side. For ' - 'example, "a[i]\n' - '+= f(x)" first looks-up "a[i]", then it evaluates "f(x)" and ' - 'performs\n' - 'the addition, and lastly, it writes the result back to ' - '"a[i]".\n' - '\n' - 'With the exception of assigning to tuples and multiple targets ' - 'in a\n' - 'single statement, the assignment done by augmented assignment\n' - 'statements is handled the same way as normal assignments. ' - 'Similarly,\n' - 'with the exception of the possible *in-place* behavior, the ' - 'binary\n' - 'operation performed by augmented assignment is the same as the ' - 'normal\n' - 'binary operations.\n' - '\n' - 'For targets which are attribute references, the same caveat ' - 'about\n' - 'class and instance attributes applies as for regular ' - 'assignments.\n' - '\n' - '\n' - 'Annotated assignment statements\n' - '===============================\n' - '\n' - 'Annotation assignment is the combination, in a single ' - 'statement, of a\n' - 'variable or attribute annotation and an optional assignment ' - 'statement:\n' - '\n' - ' annotated_assignment_stmt ::= augtarget ":" expression ["=" ' - 'expression]\n' - '\n' - 'The difference from normal Assignment statements is that only ' - 'single\n' - 'target and only single right hand side value is allowed.\n' - '\n' - 'For simple names as assignment targets, if in class or module ' - 'scope,\n' - 'the annotations are evaluated and stored in a special class or ' - 'module\n' - 'attribute "__annotations__" that is a dictionary mapping from ' - 'variable\n' - 'names (mangled if private) to evaluated annotations. This ' - 'attribute is\n' - 'writable and is automatically created at the start of class or ' - 'module\n' - 'body execution, if annotations are found statically.\n' - '\n' - 'For expressions as assignment targets, the annotations are ' - 'evaluated\n' - 'if in class or module scope, but not stored.\n' - '\n' - 'If a name is annotated in a function scope, then this name is ' - 'local\n' - 'for that scope. Annotations are never evaluated and stored in ' - 'function\n' - 'scopes.\n' - '\n' - 'If the right hand side is present, an annotated assignment ' - 'performs\n' - 'the actual assignment before evaluating annotations (where\n' - 'applicable). If the right hand side is not present for an ' - 'expression\n' - 'target, then the interpreter evaluates the target except for ' - 'the last\n' - '"__setitem__()" or "__setattr__()" call.\n' - '\n' - 'See also:\n' - '\n' - ' **PEP 526** - Syntax for Variable Annotations\n' - ' The proposal that added syntax for annotating the types ' - 'of\n' - ' variables (including class variables and instance ' - 'variables),\n' - ' instead of expressing them through comments.\n' - '\n' - ' **PEP 484** - Type hints\n' - ' The proposal that added the "typing" module to provide a ' - 'standard\n' - ' syntax for type annotations that can be used in static ' - 'analysis\n' - ' tools and IDEs.\n', - 'atom-identifiers': 'Identifiers (Names)\n' - '*******************\n' - '\n' - 'An identifier occurring as an atom is a name. See ' - 'section Identifiers\n' - 'and keywords for lexical definition and section Naming ' - 'and binding for\n' - 'documentation of naming and binding.\n' - '\n' - 'When the name is bound to an object, evaluation of the ' - 'atom yields\n' - 'that object. When a name is not bound, an attempt to ' - 'evaluate it\n' - 'raises a "NameError" exception.\n' - '\n' - '**Private name mangling:** When an identifier that ' - 'textually occurs in\n' - 'a class definition begins with two or more underscore ' - 'characters and\n' - 'does not end in two or more underscores, it is ' - 'considered a *private\n' - 'name* of that class. Private names are transformed to a ' - 'longer form\n' - 'before code is generated for them. The transformation ' - 'inserts the\n' - 'class name, with leading underscores removed and a ' - 'single underscore\n' - 'inserted, in front of the name. For example, the ' - 'identifier "__spam"\n' - 'occurring in a class named "Ham" will be transformed to ' - '"_Ham__spam".\n' - 'This transformation is independent of the syntactical ' - 'context in which\n' - 'the identifier is used. If the transformed name is ' - 'extremely long\n' - '(longer than 255 characters), implementation defined ' - 'truncation may\n' - 'happen. If the class name consists only of underscores, ' - 'no\n' - 'transformation is done.\n', - 'atom-literals': 'Literals\n' - '********\n' - '\n' - 'Python supports string and bytes literals and various ' - 'numeric\n' - 'literals:\n' - '\n' - ' literal ::= stringliteral | bytesliteral\n' - ' | integer | floatnumber | imagnumber\n' - '\n' - 'Evaluation of a literal yields an object of the given type ' - '(string,\n' - 'bytes, integer, floating point number, complex number) with ' - 'the given\n' - 'value. The value may be approximated in the case of ' - 'floating point\n' - 'and imaginary (complex) literals. See section Literals for ' - 'details.\n' - '\n' - 'All literals correspond to immutable data types, and hence ' - 'the\n' - 'object’s identity is less important than its value. ' - 'Multiple\n' - 'evaluations of literals with the same value (either the ' - 'same\n' - 'occurrence in the program text or a different occurrence) ' - 'may obtain\n' - 'the same object or a different object with the same ' - 'value.\n', - 'attribute-access': 'Customizing attribute access\n' - '****************************\n' - '\n' - 'The following methods can be defined to customize the ' - 'meaning of\n' - 'attribute access (use of, assignment to, or deletion of ' - '"x.name") for\n' - 'class instances.\n' - '\n' - 'object.__getattr__(self, name)\n' - '\n' - ' Called when the default attribute access fails with ' - 'an\n' - ' "AttributeError" (either "__getattribute__()" raises ' - 'an\n' - ' "AttributeError" because *name* is not an instance ' - 'attribute or an\n' - ' attribute in the class tree for "self"; or ' - '"__get__()" of a *name*\n' - ' property raises "AttributeError"). This method ' - 'should either\n' - ' return the (computed) attribute value or raise an ' - '"AttributeError"\n' - ' exception.\n' - '\n' - ' Note that if the attribute is found through the ' - 'normal mechanism,\n' - ' "__getattr__()" is not called. (This is an ' - 'intentional asymmetry\n' - ' between "__getattr__()" and "__setattr__()".) This is ' - 'done both for\n' - ' efficiency reasons and because otherwise ' - '"__getattr__()" would have\n' - ' no way to access other attributes of the instance. ' - 'Note that at\n' - ' least for instance variables, you can fake total ' - 'control by not\n' - ' inserting any values in the instance attribute ' - 'dictionary (but\n' - ' instead inserting them in another object). See the\n' - ' "__getattribute__()" method below for a way to ' - 'actually get total\n' - ' control over attribute access.\n' - '\n' - 'object.__getattribute__(self, name)\n' - '\n' - ' Called unconditionally to implement attribute ' - 'accesses for\n' - ' instances of the class. If the class also defines ' - '"__getattr__()",\n' - ' the latter will not be called unless ' - '"__getattribute__()" either\n' - ' calls it explicitly or raises an "AttributeError". ' - 'This method\n' - ' should return the (computed) attribute value or raise ' - 'an\n' - ' "AttributeError" exception. In order to avoid ' - 'infinite recursion in\n' - ' this method, its implementation should always call ' - 'the base class\n' - ' method with the same name to access any attributes it ' - 'needs, for\n' - ' example, "object.__getattribute__(self, name)".\n' - '\n' - ' Note: This method may still be bypassed when looking ' - 'up special\n' - ' methods as the result of implicit invocation via ' - 'language syntax\n' - ' or built-in functions. See Special method lookup.\n' - '\n' - 'object.__setattr__(self, name, value)\n' - '\n' - ' Called when an attribute assignment is attempted. ' - 'This is called\n' - ' instead of the normal mechanism (i.e. store the value ' - 'in the\n' - ' instance dictionary). *name* is the attribute name, ' - '*value* is the\n' - ' value to be assigned to it.\n' - '\n' - ' If "__setattr__()" wants to assign to an instance ' - 'attribute, it\n' - ' should call the base class method with the same name, ' - 'for example,\n' - ' "object.__setattr__(self, name, value)".\n' - '\n' - 'object.__delattr__(self, name)\n' - '\n' - ' Like "__setattr__()" but for attribute deletion ' - 'instead of\n' - ' assignment. This should only be implemented if "del ' - 'obj.name" is\n' - ' meaningful for the object.\n' - '\n' - 'object.__dir__(self)\n' - '\n' - ' Called when "dir()" is called on the object. A ' - 'sequence must be\n' - ' returned. "dir()" converts the returned sequence to a ' - 'list and\n' - ' sorts it.\n' - '\n' - '\n' - 'Customizing module attribute access\n' - '===================================\n' - '\n' - 'For a more fine grained customization of the module ' - 'behavior (setting\n' - 'attributes, properties, etc.), one can set the ' - '"__class__" attribute\n' - 'of a module object to a subclass of "types.ModuleType". ' - 'For example:\n' - '\n' - ' import sys\n' - ' from types import ModuleType\n' - '\n' - ' class VerboseModule(ModuleType):\n' - ' def __repr__(self):\n' - " return f'Verbose {self.__name__}'\n" - '\n' - ' def __setattr__(self, attr, value):\n' - " print(f'Setting {attr}...')\n" - ' setattr(self, attr, value)\n' - '\n' - ' sys.modules[__name__].__class__ = VerboseModule\n' - '\n' - 'Note: Setting module "__class__" only affects lookups ' - 'made using the\n' - ' attribute access syntax – directly accessing the ' - 'module globals\n' - ' (whether by code within the module, or via a reference ' - 'to the\n' - ' module’s globals dictionary) is unaffected.\n' - '\n' - 'Changed in version 3.5: "__class__" module attribute is ' - 'now writable.\n' - '\n' - '\n' - 'Implementing Descriptors\n' - '========================\n' - '\n' - 'The following methods only apply when an instance of the ' - 'class\n' - 'containing the method (a so-called *descriptor* class) ' - 'appears in an\n' - '*owner* class (the descriptor must be in either the ' - 'owner’s class\n' - 'dictionary or in the class dictionary for one of its ' - 'parents). In the\n' - 'examples below, “the attribute” refers to the attribute ' - 'whose name is\n' - 'the key of the property in the owner class’ "__dict__".\n' - '\n' - 'object.__get__(self, instance, owner)\n' - '\n' - ' Called to get the attribute of the owner class (class ' - 'attribute\n' - ' access) or of an instance of that class (instance ' - 'attribute\n' - ' access). *owner* is always the owner class, while ' - '*instance* is the\n' - ' instance that the attribute was accessed through, or ' - '"None" when\n' - ' the attribute is accessed through the *owner*. This ' - 'method should\n' - ' return the (computed) attribute value or raise an ' - '"AttributeError"\n' - ' exception.\n' - '\n' - 'object.__set__(self, instance, value)\n' - '\n' - ' Called to set the attribute on an instance *instance* ' - 'of the owner\n' - ' class to a new value, *value*.\n' - '\n' - 'object.__delete__(self, instance)\n' - '\n' - ' Called to delete the attribute on an instance ' - '*instance* of the\n' - ' owner class.\n' - '\n' - 'object.__set_name__(self, owner, name)\n' - '\n' - ' Called at the time the owning class *owner* is ' - 'created. The\n' - ' descriptor has been assigned to *name*.\n' - '\n' - ' New in version 3.6.\n' - '\n' - 'The attribute "__objclass__" is interpreted by the ' - '"inspect" module as\n' - 'specifying the class where this object was defined ' - '(setting this\n' - 'appropriately can assist in runtime introspection of ' - 'dynamic class\n' - 'attributes). For callables, it may indicate that an ' - 'instance of the\n' - 'given type (or a subclass) is expected or required as ' - 'the first\n' - 'positional argument (for example, CPython sets this ' - 'attribute for\n' - 'unbound methods that are implemented in C).\n' - '\n' - '\n' - 'Invoking Descriptors\n' - '====================\n' - '\n' - 'In general, a descriptor is an object attribute with ' - '“binding\n' - 'behavior”, one whose attribute access has been ' - 'overridden by methods\n' - 'in the descriptor protocol: "__get__()", "__set__()", ' - 'and\n' - '"__delete__()". If any of those methods are defined for ' - 'an object, it\n' - 'is said to be a descriptor.\n' - '\n' - 'The default behavior for attribute access is to get, ' - 'set, or delete\n' - 'the attribute from an object’s dictionary. For instance, ' - '"a.x" has a\n' - 'lookup chain starting with "a.__dict__[\'x\']", then\n' - '"type(a).__dict__[\'x\']", and continuing through the ' - 'base classes of\n' - '"type(a)" excluding metaclasses.\n' - '\n' - 'However, if the looked-up value is an object defining ' - 'one of the\n' - 'descriptor methods, then Python may override the default ' - 'behavior and\n' - 'invoke the descriptor method instead. Where this occurs ' - 'in the\n' - 'precedence chain depends on which descriptor methods ' - 'were defined and\n' - 'how they were called.\n' - '\n' - 'The starting point for descriptor invocation is a ' - 'binding, "a.x". How\n' - 'the arguments are assembled depends on "a":\n' - '\n' - 'Direct Call\n' - ' The simplest and least common call is when user code ' - 'directly\n' - ' invokes a descriptor method: "x.__get__(a)".\n' - '\n' - 'Instance Binding\n' - ' If binding to an object instance, "a.x" is ' - 'transformed into the\n' - ' call: "type(a).__dict__[\'x\'].__get__(a, type(a))".\n' - '\n' - 'Class Binding\n' - ' If binding to a class, "A.x" is transformed into the ' - 'call:\n' - ' "A.__dict__[\'x\'].__get__(None, A)".\n' - '\n' - 'Super Binding\n' - ' If "a" is an instance of "super", then the binding ' - '"super(B,\n' - ' obj).m()" searches "obj.__class__.__mro__" for the ' - 'base class "A"\n' - ' immediately preceding "B" and then invokes the ' - 'descriptor with the\n' - ' call: "A.__dict__[\'m\'].__get__(obj, ' - 'obj.__class__)".\n' - '\n' - 'For instance bindings, the precedence of descriptor ' - 'invocation depends\n' - 'on the which descriptor methods are defined. A ' - 'descriptor can define\n' - 'any combination of "__get__()", "__set__()" and ' - '"__delete__()". If it\n' - 'does not define "__get__()", then accessing the ' - 'attribute will return\n' - 'the descriptor object itself unless there is a value in ' - 'the object’s\n' - 'instance dictionary. If the descriptor defines ' - '"__set__()" and/or\n' - '"__delete__()", it is a data descriptor; if it defines ' - 'neither, it is\n' - 'a non-data descriptor. Normally, data descriptors ' - 'define both\n' - '"__get__()" and "__set__()", while non-data descriptors ' - 'have just the\n' - '"__get__()" method. Data descriptors with "__set__()" ' - 'and "__get__()"\n' - 'defined always override a redefinition in an instance ' - 'dictionary. In\n' - 'contrast, non-data descriptors can be overridden by ' - 'instances.\n' - '\n' - 'Python methods (including "staticmethod()" and ' - '"classmethod()") are\n' - 'implemented as non-data descriptors. Accordingly, ' - 'instances can\n' - 'redefine and override methods. This allows individual ' - 'instances to\n' - 'acquire behaviors that differ from other instances of ' - 'the same class.\n' - '\n' - 'The "property()" function is implemented as a data ' - 'descriptor.\n' - 'Accordingly, instances cannot override the behavior of a ' - 'property.\n' - '\n' - '\n' - '__slots__\n' - '=========\n' - '\n' - '*__slots__* allow us to explicitly declare data members ' - '(like\n' - 'properties) and deny the creation of *__dict__* and ' - '*__weakref__*\n' - '(unless explicitly declared in *__slots__* or available ' - 'in a parent.)\n' - '\n' - 'The space saved over using *__dict__* can be ' - 'significant.\n' - '\n' - 'object.__slots__\n' - '\n' - ' This class variable can be assigned a string, ' - 'iterable, or sequence\n' - ' of strings with variable names used by instances. ' - '*__slots__*\n' - ' reserves space for the declared variables and ' - 'prevents the\n' - ' automatic creation of *__dict__* and *__weakref__* ' - 'for each\n' - ' instance.\n' - '\n' - '\n' - 'Notes on using *__slots__*\n' - '--------------------------\n' - '\n' - '* When inheriting from a class without *__slots__*, the ' - '*__dict__*\n' - ' and *__weakref__* attribute of the instances will ' - 'always be\n' - ' accessible.\n' - '\n' - '* Without a *__dict__* variable, instances cannot be ' - 'assigned new\n' - ' variables not listed in the *__slots__* definition. ' - 'Attempts to\n' - ' assign to an unlisted variable name raises ' - '"AttributeError". If\n' - ' dynamic assignment of new variables is desired, then ' - 'add\n' - ' "\'__dict__\'" to the sequence of strings in the ' - '*__slots__*\n' - ' declaration.\n' - '\n' - '* Without a *__weakref__* variable for each instance, ' - 'classes\n' - ' defining *__slots__* do not support weak references to ' - 'its\n' - ' instances. If weak reference support is needed, then ' - 'add\n' - ' "\'__weakref__\'" to the sequence of strings in the ' - '*__slots__*\n' - ' declaration.\n' - '\n' - '* *__slots__* are implemented at the class level by ' - 'creating\n' - ' descriptors (Implementing Descriptors) for each ' - 'variable name. As a\n' - ' result, class attributes cannot be used to set default ' - 'values for\n' - ' instance variables defined by *__slots__*; otherwise, ' - 'the class\n' - ' attribute would overwrite the descriptor assignment.\n' - '\n' - '* The action of a *__slots__* declaration is not limited ' - 'to the\n' - ' class where it is defined. *__slots__* declared in ' - 'parents are\n' - ' available in child classes. However, child subclasses ' - 'will get a\n' - ' *__dict__* and *__weakref__* unless they also define ' - '*__slots__*\n' - ' (which should only contain names of any *additional* ' - 'slots).\n' - '\n' - '* If a class defines a slot also defined in a base ' - 'class, the\n' - ' instance variable defined by the base class slot is ' - 'inaccessible\n' - ' (except by retrieving its descriptor directly from the ' - 'base class).\n' - ' This renders the meaning of the program undefined. In ' - 'the future, a\n' - ' check may be added to prevent this.\n' - '\n' - '* Nonempty *__slots__* does not work for classes derived ' - 'from\n' - ' “variable-length” built-in types such as "int", ' - '"bytes" and "tuple".\n' - '\n' - '* Any non-string iterable may be assigned to ' - '*__slots__*. Mappings\n' - ' may also be used; however, in the future, special ' - 'meaning may be\n' - ' assigned to the values corresponding to each key.\n' - '\n' - '* *__class__* assignment works only if both classes have ' - 'the same\n' - ' *__slots__*.\n' - '\n' - '* Multiple inheritance with multiple slotted parent ' - 'classes can be\n' - ' used, but only one parent is allowed to have ' - 'attributes created by\n' - ' slots (the other bases must have empty slot layouts) - ' - 'violations\n' - ' raise "TypeError".\n', - 'attribute-references': 'Attribute references\n' - '********************\n' - '\n' - 'An attribute reference is a primary followed by a ' - 'period and a name:\n' - '\n' - ' attributeref ::= primary "." identifier\n' - '\n' - 'The primary must evaluate to an object of a type ' - 'that supports\n' - 'attribute references, which most objects do. This ' - 'object is then\n' - 'asked to produce the attribute whose name is the ' - 'identifier. This\n' - 'production can be customized by overriding the ' - '"__getattr__()" method.\n' - 'If this attribute is not available, the exception ' - '"AttributeError" is\n' - 'raised. Otherwise, the type and value of the object ' - 'produced is\n' - 'determined by the object. Multiple evaluations of ' - 'the same attribute\n' - 'reference may yield different objects.\n', - 'augassign': 'Augmented assignment statements\n' - '*******************************\n' - '\n' - 'Augmented assignment is the combination, in a single statement, ' - 'of a\n' - 'binary operation and an assignment statement:\n' - '\n' - ' augmented_assignment_stmt ::= augtarget augop ' - '(expression_list | yield_expression)\n' - ' augtarget ::= identifier | attributeref | ' - 'subscription | slicing\n' - ' augop ::= "+=" | "-=" | "*=" | "@=" | ' - '"/=" | "//=" | "%=" | "**="\n' - ' | ">>=" | "<<=" | "&=" | "^=" | "|="\n' - '\n' - '(See section Primaries for the syntax definitions of the last ' - 'three\n' - 'symbols.)\n' - '\n' - 'An augmented assignment evaluates the target (which, unlike ' - 'normal\n' - 'assignment statements, cannot be an unpacking) and the ' - 'expression\n' - 'list, performs the binary operation specific to the type of ' - 'assignment\n' - 'on the two operands, and assigns the result to the original ' - 'target.\n' - 'The target is only evaluated once.\n' - '\n' - 'An augmented assignment expression like "x += 1" can be ' - 'rewritten as\n' - '"x = x + 1" to achieve a similar, but not exactly equal effect. ' - 'In the\n' - 'augmented version, "x" is only evaluated once. Also, when ' - 'possible,\n' - 'the actual operation is performed *in-place*, meaning that ' - 'rather than\n' - 'creating a new object and assigning that to the target, the old ' - 'object\n' - 'is modified instead.\n' - '\n' - 'Unlike normal assignments, augmented assignments evaluate the ' - 'left-\n' - 'hand side *before* evaluating the right-hand side. For ' - 'example, "a[i]\n' - '+= f(x)" first looks-up "a[i]", then it evaluates "f(x)" and ' - 'performs\n' - 'the addition, and lastly, it writes the result back to "a[i]".\n' - '\n' - 'With the exception of assigning to tuples and multiple targets ' - 'in a\n' - 'single statement, the assignment done by augmented assignment\n' - 'statements is handled the same way as normal assignments. ' - 'Similarly,\n' - 'with the exception of the possible *in-place* behavior, the ' - 'binary\n' - 'operation performed by augmented assignment is the same as the ' - 'normal\n' - 'binary operations.\n' - '\n' - 'For targets which are attribute references, the same caveat ' - 'about\n' - 'class and instance attributes applies as for regular ' - 'assignments.\n', - 'binary': 'Binary arithmetic operations\n' - '****************************\n' - '\n' - 'The binary arithmetic operations have the conventional priority\n' - 'levels. Note that some of these operations also apply to certain ' - 'non-\n' - 'numeric types. Apart from the power operator, there are only two\n' - 'levels, one for multiplicative operators and one for additive\n' - 'operators:\n' - '\n' - ' m_expr ::= u_expr | m_expr "*" u_expr | m_expr "@" m_expr |\n' - ' m_expr "//" u_expr | m_expr "/" u_expr |\n' - ' m_expr "%" u_expr\n' - ' a_expr ::= m_expr | a_expr "+" m_expr | a_expr "-" m_expr\n' - '\n' - 'The "*" (multiplication) operator yields the product of its ' - 'arguments.\n' - 'The arguments must either both be numbers, or one argument must be ' - 'an\n' - 'integer and the other must be a sequence. In the former case, the\n' - 'numbers are converted to a common type and then multiplied ' - 'together.\n' - 'In the latter case, sequence repetition is performed; a negative\n' - 'repetition factor yields an empty sequence.\n' - '\n' - 'The "@" (at) operator is intended to be used for matrix\n' - 'multiplication. No builtin Python types implement this operator.\n' - '\n' - 'New in version 3.5.\n' - '\n' - 'The "/" (division) and "//" (floor division) operators yield the\n' - 'quotient of their arguments. The numeric arguments are first\n' - 'converted to a common type. Division of integers yields a float, ' - 'while\n' - 'floor division of integers results in an integer; the result is ' - 'that\n' - 'of mathematical division with the ‘floor’ function applied to the\n' - 'result. Division by zero raises the "ZeroDivisionError" ' - 'exception.\n' - '\n' - 'The "%" (modulo) operator yields the remainder from the division ' - 'of\n' - 'the first argument by the second. The numeric arguments are ' - 'first\n' - 'converted to a common type. A zero right argument raises the\n' - '"ZeroDivisionError" exception. The arguments may be floating ' - 'point\n' - 'numbers, e.g., "3.14%0.7" equals "0.34" (since "3.14" equals ' - '"4*0.7 +\n' - '0.34".) The modulo operator always yields a result with the same ' - 'sign\n' - 'as its second operand (or zero); the absolute value of the result ' - 'is\n' - 'strictly smaller than the absolute value of the second operand ' - '[1].\n' - '\n' - 'The floor division and modulo operators are connected by the ' - 'following\n' - 'identity: "x == (x//y)*y + (x%y)". Floor division and modulo are ' - 'also\n' - 'connected with the built-in function "divmod()": "divmod(x, y) ==\n' - '(x//y, x%y)". [2].\n' - '\n' - 'In addition to performing the modulo operation on numbers, the ' - '"%"\n' - 'operator is also overloaded by string objects to perform ' - 'old-style\n' - 'string formatting (also known as interpolation). The syntax for\n' - 'string formatting is described in the Python Library Reference,\n' - 'section printf-style String Formatting.\n' - '\n' - 'The floor division operator, the modulo operator, and the ' - '"divmod()"\n' - 'function are not defined for complex numbers. Instead, convert to ' - 'a\n' - 'floating point number using the "abs()" function if appropriate.\n' - '\n' - 'The "+" (addition) operator yields the sum of its arguments. The\n' - 'arguments must either both be numbers or both be sequences of the ' - 'same\n' - 'type. In the former case, the numbers are converted to a common ' - 'type\n' - 'and then added together. In the latter case, the sequences are\n' - 'concatenated.\n' - '\n' - 'The "-" (subtraction) operator yields the difference of its ' - 'arguments.\n' - 'The numeric arguments are first converted to a common type.\n', - 'bitwise': 'Binary bitwise operations\n' - '*************************\n' - '\n' - 'Each of the three bitwise operations has a different priority ' - 'level:\n' - '\n' - ' and_expr ::= shift_expr | and_expr "&" shift_expr\n' - ' xor_expr ::= and_expr | xor_expr "^" and_expr\n' - ' or_expr ::= xor_expr | or_expr "|" xor_expr\n' - '\n' - 'The "&" operator yields the bitwise AND of its arguments, which ' - 'must\n' - 'be integers.\n' - '\n' - 'The "^" operator yields the bitwise XOR (exclusive OR) of its\n' - 'arguments, which must be integers.\n' - '\n' - 'The "|" operator yields the bitwise (inclusive) OR of its ' - 'arguments,\n' - 'which must be integers.\n', - 'bltin-code-objects': 'Code Objects\n' - '************\n' + '**********************\n' + '\n' + 'Assert statements are a convenient way to insert debugging ' + 'assertions\n' + 'into a program:\n' + '\n' + ' assert_stmt ::= "assert" expression ["," expression]\n' + '\n' + 'The simple form, "assert expression", is equivalent to\n' + '\n' + ' if __debug__:\n' + ' if not expression: raise AssertionError\n' + '\n' + 'The extended form, "assert expression1, expression2", is ' + 'equivalent to\n' + '\n' + ' if __debug__:\n' + ' if not expression1: raise AssertionError(expression2)\n' + '\n' + 'These equivalences assume that "__debug__" and "AssertionError" ' + 'refer\n' + 'to the built-in variables with those names. In the current\n' + 'implementation, the built-in variable "__debug__" is "True" under\n' + 'normal circumstances, "False" when optimization is requested ' + '(command\n' + 'line option "-O"). The current code generator emits no code for ' + 'an\n' + '"assert" statement when optimization is requested at compile ' + 'time.\n' + 'Note that it is unnecessary to include the source code for the\n' + 'expression that failed in the error message; it will be displayed ' + 'as\n' + 'part of the stack trace.\n' + '\n' + 'Assignments to "__debug__" are illegal. The value for the ' + 'built-in\n' + 'variable is determined when the interpreter starts.\n', + 'assignment': 'Assignment statements\n' + '*********************\n' + '\n' + 'Assignment statements are used to (re)bind names to values and ' + 'to\n' + 'modify attributes or items of mutable objects:\n' + '\n' + ' assignment_stmt ::= (target_list "=")+ (starred_expression ' + '| yield_expression)\n' + ' target_list ::= target ("," target)* [","]\n' + ' target ::= identifier\n' + ' | "(" [target_list] ")"\n' + ' | "[" [target_list] "]"\n' + ' | attributeref\n' + ' | subscription\n' + ' | slicing\n' + ' | "*" target\n' + '\n' + '(See section Primaries for the syntax definitions for ' + '*attributeref*,\n' + '*subscription*, and *slicing*.)\n' + '\n' + 'An assignment statement evaluates the expression list ' + '(remember that\n' + 'this can be a single expression or a comma-separated list, the ' + 'latter\n' + 'yielding a tuple) and assigns the single resulting object to ' + 'each of\n' + 'the target lists, from left to right.\n' + '\n' + 'Assignment is defined recursively depending on the form of the ' + 'target\n' + '(list). When a target is part of a mutable object (an ' + 'attribute\n' + 'reference, subscription or slicing), the mutable object must\n' + 'ultimately perform the assignment and decide about its ' + 'validity, and\n' + 'may raise an exception if the assignment is unacceptable. The ' + 'rules\n' + 'observed by various types and the exceptions raised are given ' + 'with the\n' + 'definition of the object types (see section The standard type\n' + 'hierarchy).\n' + '\n' + 'Assignment of an object to a target list, optionally enclosed ' + 'in\n' + 'parentheses or square brackets, is recursively defined as ' + 'follows.\n' + '\n' + '* If the target list is a single target with no trailing ' + 'comma,\n' + ' optionally in parentheses, the object is assigned to that ' + 'target.\n' + '\n' + '* Else:\n' + '\n' + ' * If the target list contains one target prefixed with an ' + 'asterisk,\n' + ' called a “starred” target: The object must be an iterable ' + 'with at\n' + ' least as many items as there are targets in the target ' + 'list, minus\n' + ' one. The first items of the iterable are assigned, from ' + 'left to\n' + ' right, to the targets before the starred target. The ' + 'final items\n' + ' of the iterable are assigned to the targets after the ' + 'starred\n' + ' target. A list of the remaining items in the iterable is ' + 'then\n' + ' assigned to the starred target (the list can be empty).\n' + '\n' + ' * Else: The object must be an iterable with the same number ' + 'of items\n' + ' as there are targets in the target list, and the items ' + 'are\n' + ' assigned, from left to right, to the corresponding ' + 'targets.\n' + '\n' + 'Assignment of an object to a single target is recursively ' + 'defined as\n' + 'follows.\n' + '\n' + '* If the target is an identifier (name):\n' + '\n' + ' * If the name does not occur in a "global" or "nonlocal" ' + 'statement\n' + ' in the current code block: the name is bound to the object ' + 'in the\n' + ' current local namespace.\n' + '\n' + ' * Otherwise: the name is bound to the object in the global ' + 'namespace\n' + ' or the outer namespace determined by "nonlocal", ' + 'respectively.\n' + '\n' + ' The name is rebound if it was already bound. This may cause ' + 'the\n' + ' reference count for the object previously bound to the name ' + 'to reach\n' + ' zero, causing the object to be deallocated and its ' + 'destructor (if it\n' + ' has one) to be called.\n' + '\n' + '* If the target is an attribute reference: The primary ' + 'expression in\n' + ' the reference is evaluated. It should yield an object with\n' + ' assignable attributes; if this is not the case, "TypeError" ' + 'is\n' + ' raised. That object is then asked to assign the assigned ' + 'object to\n' + ' the given attribute; if it cannot perform the assignment, it ' + 'raises\n' + ' an exception (usually but not necessarily ' + '"AttributeError").\n' + '\n' + ' Note: If the object is a class instance and the attribute ' + 'reference\n' + ' occurs on both sides of the assignment operator, the ' + 'right-hand side\n' + ' expression, "a.x" can access either an instance attribute or ' + '(if no\n' + ' instance attribute exists) a class attribute. The left-hand ' + 'side\n' + ' target "a.x" is always set as an instance attribute, ' + 'creating it if\n' + ' necessary. Thus, the two occurrences of "a.x" do not ' + 'necessarily\n' + ' refer to the same attribute: if the right-hand side ' + 'expression\n' + ' refers to a class attribute, the left-hand side creates a ' + 'new\n' + ' instance attribute as the target of the assignment:\n' + '\n' + ' class Cls:\n' + ' x = 3 # class variable\n' + ' inst = Cls()\n' + ' inst.x = inst.x + 1 # writes inst.x as 4 leaving Cls.x ' + 'as 3\n' + '\n' + ' This description does not necessarily apply to descriptor\n' + ' attributes, such as properties created with "property()".\n' + '\n' + '* If the target is a subscription: The primary expression in ' + 'the\n' + ' reference is evaluated. It should yield either a mutable ' + 'sequence\n' + ' object (such as a list) or a mapping object (such as a ' + 'dictionary).\n' + ' Next, the subscript expression is evaluated.\n' + '\n' + ' If the primary is a mutable sequence object (such as a ' + 'list), the\n' + ' subscript must yield an integer. If it is negative, the ' + 'sequence’s\n' + ' length is added to it. The resulting value must be a ' + 'nonnegative\n' + ' integer less than the sequence’s length, and the sequence is ' + 'asked\n' + ' to assign the assigned object to its item with that index. ' + 'If the\n' + ' index is out of range, "IndexError" is raised (assignment to ' + 'a\n' + ' subscripted sequence cannot add new items to a list).\n' + '\n' + ' If the primary is a mapping object (such as a dictionary), ' + 'the\n' + ' subscript must have a type compatible with the mapping’s key ' + 'type,\n' + ' and the mapping is then asked to create a key/value pair ' + 'which maps\n' + ' the subscript to the assigned object. This can either ' + 'replace an\n' + ' existing key/value pair with the same key value, or insert a ' + 'new\n' + ' key/value pair (if no key with the same value existed).\n' + '\n' + ' For user-defined objects, the "__setitem__()" method is ' + 'called with\n' + ' appropriate arguments.\n' + '\n' + '* If the target is a slicing: The primary expression in the ' + 'reference\n' + ' is evaluated. It should yield a mutable sequence object ' + '(such as a\n' + ' list). The assigned object should be a sequence object of ' + 'the same\n' + ' type. Next, the lower and upper bound expressions are ' + 'evaluated,\n' + ' insofar they are present; defaults are zero and the ' + 'sequence’s\n' + ' length. The bounds should evaluate to integers. If either ' + 'bound is\n' + ' negative, the sequence’s length is added to it. The ' + 'resulting\n' + ' bounds are clipped to lie between zero and the sequence’s ' + 'length,\n' + ' inclusive. Finally, the sequence object is asked to replace ' + 'the\n' + ' slice with the items of the assigned sequence. The length ' + 'of the\n' + ' slice may be different from the length of the assigned ' + 'sequence,\n' + ' thus changing the length of the target sequence, if the ' + 'target\n' + ' sequence allows it.\n' + '\n' + '**CPython implementation detail:** In the current ' + 'implementation, the\n' + 'syntax for targets is taken to be the same as for expressions, ' + 'and\n' + 'invalid syntax is rejected during the code generation phase, ' + 'causing\n' + 'less detailed error messages.\n' + '\n' + 'Although the definition of assignment implies that overlaps ' + 'between\n' + 'the left-hand side and the right-hand side are ‘simultaneous’ ' + '(for\n' + 'example "a, b = b, a" swaps two variables), overlaps *within* ' + 'the\n' + 'collection of assigned-to variables occur left-to-right, ' + 'sometimes\n' + 'resulting in confusion. For instance, the following program ' + 'prints\n' + '"[0, 2]":\n' + '\n' + ' x = [0, 1]\n' + ' i = 0\n' + ' i, x[i] = 1, 2 # i is updated, then x[i] is ' + 'updated\n' + ' print(x)\n' + '\n' + 'See also:\n' + '\n' + ' **PEP 3132** - Extended Iterable Unpacking\n' + ' The specification for the "*target" feature.\n' + '\n' + '\n' + 'Augmented assignment statements\n' + '===============================\n' + '\n' + 'Augmented assignment is the combination, in a single ' + 'statement, of a\n' + 'binary operation and an assignment statement:\n' + '\n' + ' augmented_assignment_stmt ::= augtarget augop ' + '(expression_list | yield_expression)\n' + ' augtarget ::= identifier | attributeref | ' + 'subscription | slicing\n' + ' augop ::= "+=" | "-=" | "*=" | "@=" | ' + '"/=" | "//=" | "%=" | "**="\n' + ' | ">>=" | "<<=" | "&=" | "^=" | "|="\n' + '\n' + '(See section Primaries for the syntax definitions of the last ' + 'three\n' + 'symbols.)\n' + '\n' + 'An augmented assignment evaluates the target (which, unlike ' + 'normal\n' + 'assignment statements, cannot be an unpacking) and the ' + 'expression\n' + 'list, performs the binary operation specific to the type of ' + 'assignment\n' + 'on the two operands, and assigns the result to the original ' + 'target.\n' + 'The target is only evaluated once.\n' + '\n' + 'An augmented assignment statement like "x += 1" can be ' + 'rewritten as "x\n' + '= x + 1" to achieve a similar, but not exactly equal effect. ' + 'In the\n' + 'augmented version, "x" is only evaluated once. Also, when ' + 'possible,\n' + 'the actual operation is performed *in-place*, meaning that ' + 'rather than\n' + 'creating a new object and assigning that to the target, the ' + 'old object\n' + 'is modified instead.\n' + '\n' + 'Unlike normal assignments, augmented assignments evaluate the ' + 'left-\n' + 'hand side *before* evaluating the right-hand side. For ' + 'example, "a[i]\n' + '+= f(x)" first looks-up "a[i]", then it evaluates "f(x)" and ' + 'performs\n' + 'the addition, and lastly, it writes the result back to ' + '"a[i]".\n' + '\n' + 'With the exception of assigning to tuples and multiple targets ' + 'in a\n' + 'single statement, the assignment done by augmented assignment\n' + 'statements is handled the same way as normal assignments. ' + 'Similarly,\n' + 'with the exception of the possible *in-place* behavior, the ' + 'binary\n' + 'operation performed by augmented assignment is the same as the ' + 'normal\n' + 'binary operations.\n' + '\n' + 'For targets which are attribute references, the same caveat ' + 'about\n' + 'class and instance attributes applies as for regular ' + 'assignments.\n' + '\n' + '\n' + 'Annotated assignment statements\n' + '===============================\n' + '\n' + '*Annotation* assignment is the combination, in a single ' + 'statement, of\n' + 'a variable or attribute annotation and an optional assignment\n' + 'statement:\n' + '\n' + ' annotated_assignment_stmt ::= augtarget ":" expression\n' + ' ["=" (starred_expression | ' + 'yield_expression)]\n' + '\n' + 'The difference from normal Assignment statements is that only ' + 'a single\n' + 'target is allowed.\n' + '\n' + 'The assignment target is considered “simple” if it consists of ' + 'a\n' + 'single name that is not enclosed in parentheses. For simple ' + 'assignment\n' + 'targets, if in class or module scope, the annotations are ' + 'evaluated\n' + 'and stored in a special class or module attribute ' + '"__annotations__"\n' + 'that is a dictionary mapping from variable names (mangled if ' + 'private)\n' + 'to evaluated annotations. This attribute is writable and is\n' + 'automatically created at the start of class or module body ' + 'execution,\n' + 'if annotations are found statically.\n' + '\n' + 'If the assignment target is not simple (an attribute, ' + 'subscript node,\n' + 'or parenthesized name), the annotation is evaluated if in ' + 'class or\n' + 'module scope, but not stored.\n' + '\n' + 'If a name is annotated in a function scope, then this name is ' + 'local\n' + 'for that scope. Annotations are never evaluated and stored in ' + 'function\n' + 'scopes.\n' + '\n' + 'If the right hand side is present, an annotated assignment ' + 'performs\n' + 'the actual assignment before evaluating annotations (where\n' + 'applicable). If the right hand side is not present for an ' + 'expression\n' + 'target, then the interpreter evaluates the target except for ' + 'the last\n' + '"__setitem__()" or "__setattr__()" call.\n' + '\n' + 'See also:\n' + '\n' + ' **PEP 526** - Syntax for Variable Annotations\n' + ' The proposal that added syntax for annotating the types ' + 'of\n' + ' variables (including class variables and instance ' + 'variables),\n' + ' instead of expressing them through comments.\n' + '\n' + ' **PEP 484** - Type hints\n' + ' The proposal that added the "typing" module to provide a ' + 'standard\n' + ' syntax for type annotations that can be used in static ' + 'analysis\n' + ' tools and IDEs.\n' + '\n' + 'Changed in version 3.8: Now annotated assignments allow the ' + 'same\n' + 'expressions in the right hand side as regular assignments. ' + 'Previously,\n' + 'some expressions (like un-parenthesized tuple expressions) ' + 'caused a\n' + 'syntax error.\n', + 'async': 'Coroutines\n' + '**********\n' + '\n' + 'Added in version 3.5.\n' + '\n' + '\n' + 'Coroutine function definition\n' + '=============================\n' + '\n' + ' async_funcdef ::= [decorators] "async" "def" funcname "(" ' + '[parameter_list] ")"\n' + ' ["->" expression] ":" suite\n' + '\n' + 'Execution of Python coroutines can be suspended and resumed at ' + 'many\n' + 'points (see *coroutine*). "await" expressions, "async for" and ' + '"async\n' + 'with" can only be used in the body of a coroutine function.\n' + '\n' + 'Functions defined with "async def" syntax are always coroutine\n' + 'functions, even if they do not contain "await" or "async" ' + 'keywords.\n' + '\n' + 'It is a "SyntaxError" to use a "yield from" expression inside the ' + 'body\n' + 'of a coroutine function.\n' + '\n' + 'An example of a coroutine function:\n' + '\n' + ' async def func(param1, param2):\n' + ' do_stuff()\n' + ' await some_coroutine()\n' + '\n' + 'Changed in version 3.7: "await" and "async" are now keywords;\n' + 'previously they were only treated as such inside the body of a\n' + 'coroutine function.\n' + '\n' + '\n' + 'The "async for" statement\n' + '=========================\n' + '\n' + ' async_for_stmt ::= "async" for_stmt\n' + '\n' + 'An *asynchronous iterable* provides an "__aiter__" method that\n' + 'directly returns an *asynchronous iterator*, which can call\n' + 'asynchronous code in its "__anext__" method.\n' + '\n' + 'The "async for" statement allows convenient iteration over\n' + 'asynchronous iterables.\n' + '\n' + 'The following code:\n' + '\n' + ' async for TARGET in ITER:\n' + ' SUITE\n' + ' else:\n' + ' SUITE2\n' + '\n' + 'Is semantically equivalent to:\n' + '\n' + ' iter = (ITER)\n' + ' iter = type(iter).__aiter__(iter)\n' + ' running = True\n' + '\n' + ' while running:\n' + ' try:\n' + ' TARGET = await type(iter).__anext__(iter)\n' + ' except StopAsyncIteration:\n' + ' running = False\n' + ' else:\n' + ' SUITE\n' + ' else:\n' + ' SUITE2\n' + '\n' + 'See also "__aiter__()" and "__anext__()" for details.\n' + '\n' + 'It is a "SyntaxError" to use an "async for" statement outside the ' + 'body\n' + 'of a coroutine function.\n' + '\n' + '\n' + 'The "async with" statement\n' + '==========================\n' + '\n' + ' async_with_stmt ::= "async" with_stmt\n' + '\n' + 'An *asynchronous context manager* is a *context manager* that is ' + 'able\n' + 'to suspend execution in its *enter* and *exit* methods.\n' + '\n' + 'The following code:\n' + '\n' + ' async with EXPRESSION as TARGET:\n' + ' SUITE\n' + '\n' + 'is semantically equivalent to:\n' + '\n' + ' manager = (EXPRESSION)\n' + ' aenter = type(manager).__aenter__\n' + ' aexit = type(manager).__aexit__\n' + ' value = await aenter(manager)\n' + ' hit_except = False\n' + '\n' + ' try:\n' + ' TARGET = value\n' + ' SUITE\n' + ' except:\n' + ' hit_except = True\n' + ' if not await aexit(manager, *sys.exc_info()):\n' + ' raise\n' + ' finally:\n' + ' if not hit_except:\n' + ' await aexit(manager, None, None, None)\n' + '\n' + 'See also "__aenter__()" and "__aexit__()" for details.\n' + '\n' + 'It is a "SyntaxError" to use an "async with" statement outside the\n' + 'body of a coroutine function.\n' + '\n' + 'See also:\n' + '\n' + ' **PEP 492** - Coroutines with async and await syntax\n' + ' The proposal that made coroutines a proper standalone concept ' + 'in\n' + ' Python, and added supporting syntax.\n', + 'atom-identifiers': 'Identifiers (Names)\n' + '*******************\n' + '\n' + 'An identifier occurring as an atom is a name. See ' + 'section Identifiers\n' + 'and keywords for lexical definition and section Naming ' + 'and binding for\n' + 'documentation of naming and binding.\n' + '\n' + 'When the name is bound to an object, evaluation of the ' + 'atom yields\n' + 'that object. When a name is not bound, an attempt to ' + 'evaluate it\n' + 'raises a "NameError" exception.\n' + '\n' + '\n' + 'Private name mangling\n' + '=====================\n' + '\n' + 'When an identifier that textually occurs in a class ' + 'definition begins\n' + 'with two or more underscore characters and does not end ' + 'in two or more\n' + 'underscores, it is considered a *private name* of that ' + 'class.\n' + '\n' + 'See also: The class specifications.\n' + '\n' + 'More precisely, private names are transformed to a ' + 'longer form before\n' + 'code is generated for them. If the transformed name is ' + 'longer than\n' + '255 characters, implementation-defined truncation may ' + 'happen.\n' + '\n' + 'The transformation is independent of the syntactical ' + 'context in which\n' + 'the identifier is used but only the following private ' + 'identifiers are\n' + 'mangled:\n' + '\n' + '* Any name used as the name of a variable that is ' + 'assigned or read or\n' + ' any name of an attribute being accessed.\n' + '\n' + ' The "__name__" attribute of nested functions, classes, ' + 'and type\n' + ' aliases is however not mangled.\n' + '\n' + '* The name of imported modules, e.g., "__spam" in ' + '"import __spam". If\n' + ' the module is part of a package (i.e., its name ' + 'contains a dot), the\n' + ' name is *not* mangled, e.g., the "__foo" in "import ' + '__foo.bar" is\n' + ' not mangled.\n' + '\n' + '* The name of an imported member, e.g., "__f" in "from ' + 'spam import\n' + ' __f".\n' + '\n' + 'The transformation rule is defined as follows:\n' + '\n' + '* The class name, with leading underscores removed and a ' + 'single\n' + ' leading underscore inserted, is inserted in front of ' + 'the identifier,\n' + ' e.g., the identifier "__spam" occurring in a class ' + 'named "Foo",\n' + ' "_Foo" or "__Foo" is transformed to "_Foo__spam".\n' + '\n' + '* If the class name consists only of underscores, the ' + 'transformation\n' + ' is the identity, e.g., the identifier "__spam" ' + 'occurring in a class\n' + ' named "_" or "__" is left as is.\n', + 'atom-literals': 'Literals\n' + '********\n' + '\n' + 'Python supports string and bytes literals and various ' + 'numeric\n' + 'literals:\n' + '\n' + ' literal ::= stringliteral | bytesliteral\n' + ' | integer | floatnumber | imagnumber\n' + '\n' + 'Evaluation of a literal yields an object of the given type ' + '(string,\n' + 'bytes, integer, floating-point number, complex number) with ' + 'the given\n' + 'value. The value may be approximated in the case of ' + 'floating-point\n' + 'and imaginary (complex) literals. See section Literals for ' + 'details.\n' + '\n' + 'All literals correspond to immutable data types, and hence ' + 'the\n' + 'object’s identity is less important than its value. ' + 'Multiple\n' + 'evaluations of literals with the same value (either the ' + 'same\n' + 'occurrence in the program text or a different occurrence) ' + 'may obtain\n' + 'the same object or a different object with the same ' + 'value.\n', + 'attribute-access': 'Customizing attribute access\n' + '****************************\n' + '\n' + 'The following methods can be defined to customize the ' + 'meaning of\n' + 'attribute access (use of, assignment to, or deletion of ' + '"x.name") for\n' + 'class instances.\n' + '\n' + 'object.__getattr__(self, name)\n' + '\n' + ' Called when the default attribute access fails with ' + 'an\n' + ' "AttributeError" (either "__getattribute__()" raises ' + 'an\n' + ' "AttributeError" because *name* is not an instance ' + 'attribute or an\n' + ' attribute in the class tree for "self"; or ' + '"__get__()" of a *name*\n' + ' property raises "AttributeError"). This method ' + 'should either\n' + ' return the (computed) attribute value or raise an ' + '"AttributeError"\n' + ' exception. The "object" class itself does not provide ' + 'this method.\n' + '\n' + ' Note that if the attribute is found through the ' + 'normal mechanism,\n' + ' "__getattr__()" is not called. (This is an ' + 'intentional asymmetry\n' + ' between "__getattr__()" and "__setattr__()".) This is ' + 'done both for\n' + ' efficiency reasons and because otherwise ' + '"__getattr__()" would have\n' + ' no way to access other attributes of the instance. ' + 'Note that at\n' + ' least for instance variables, you can fake total ' + 'control by not\n' + ' inserting any values in the instance attribute ' + 'dictionary (but\n' + ' instead inserting them in another object). See the\n' + ' "__getattribute__()" method below for a way to ' + 'actually get total\n' + ' control over attribute access.\n' + '\n' + 'object.__getattribute__(self, name)\n' + '\n' + ' Called unconditionally to implement attribute ' + 'accesses for\n' + ' instances of the class. If the class also defines ' + '"__getattr__()",\n' + ' the latter will not be called unless ' + '"__getattribute__()" either\n' + ' calls it explicitly or raises an "AttributeError". ' + 'This method\n' + ' should return the (computed) attribute value or raise ' + 'an\n' + ' "AttributeError" exception. In order to avoid ' + 'infinite recursion in\n' + ' this method, its implementation should always call ' + 'the base class\n' + ' method with the same name to access any attributes it ' + 'needs, for\n' + ' example, "object.__getattribute__(self, name)".\n' + '\n' + ' Note:\n' + '\n' + ' This method may still be bypassed when looking up ' + 'special methods\n' + ' as the result of implicit invocation via language ' + 'syntax or\n' + ' built-in functions. See Special method lookup.\n' + '\n' + ' For certain sensitive attribute accesses, raises an ' + 'auditing event\n' + ' "object.__getattr__" with arguments "obj" and ' + '"name".\n' + '\n' + 'object.__setattr__(self, name, value)\n' + '\n' + ' Called when an attribute assignment is attempted. ' + 'This is called\n' + ' instead of the normal mechanism (i.e. store the value ' + 'in the\n' + ' instance dictionary). *name* is the attribute name, ' + '*value* is the\n' + ' value to be assigned to it.\n' + '\n' + ' If "__setattr__()" wants to assign to an instance ' + 'attribute, it\n' + ' should call the base class method with the same name, ' + 'for example,\n' + ' "object.__setattr__(self, name, value)".\n' + '\n' + ' For certain sensitive attribute assignments, raises ' + 'an auditing\n' + ' event "object.__setattr__" with arguments "obj", ' + '"name", "value".\n' + '\n' + 'object.__delattr__(self, name)\n' + '\n' + ' Like "__setattr__()" but for attribute deletion ' + 'instead of\n' + ' assignment. This should only be implemented if "del ' + 'obj.name" is\n' + ' meaningful for the object.\n' + '\n' + ' For certain sensitive attribute deletions, raises an ' + 'auditing event\n' + ' "object.__delattr__" with arguments "obj" and ' + '"name".\n' + '\n' + 'object.__dir__(self)\n' + '\n' + ' Called when "dir()" is called on the object. An ' + 'iterable must be\n' + ' returned. "dir()" converts the returned iterable to a ' + 'list and\n' + ' sorts it.\n' + '\n' + '\n' + 'Customizing module attribute access\n' + '===================================\n' + '\n' + 'Special names "__getattr__" and "__dir__" can be also ' + 'used to\n' + 'customize access to module attributes. The "__getattr__" ' + 'function at\n' + 'the module level should accept one argument which is the ' + 'name of an\n' + 'attribute and return the computed value or raise an ' + '"AttributeError".\n' + 'If an attribute is not found on a module object through ' + 'the normal\n' + 'lookup, i.e. "object.__getattribute__()", then ' + '"__getattr__" is\n' + 'searched in the module "__dict__" before raising an ' + '"AttributeError".\n' + 'If found, it is called with the attribute name and the ' + 'result is\n' + 'returned.\n' + '\n' + 'The "__dir__" function should accept no arguments, and ' + 'return an\n' + 'iterable of strings that represents the names accessible ' + 'on module. If\n' + 'present, this function overrides the standard "dir()" ' + 'search on a\n' + 'module.\n' + '\n' + 'For a more fine grained customization of the module ' + 'behavior (setting\n' + 'attributes, properties, etc.), one can set the ' + '"__class__" attribute\n' + 'of a module object to a subclass of "types.ModuleType". ' + 'For example:\n' + '\n' + ' import sys\n' + ' from types import ModuleType\n' + '\n' + ' class VerboseModule(ModuleType):\n' + ' def __repr__(self):\n' + " return f'Verbose {self.__name__}'\n" + '\n' + ' def __setattr__(self, attr, value):\n' + " print(f'Setting {attr}...')\n" + ' super().__setattr__(attr, value)\n' + '\n' + ' sys.modules[__name__].__class__ = VerboseModule\n' + '\n' + 'Note:\n' + '\n' + ' Defining module "__getattr__" and setting module ' + '"__class__" only\n' + ' affect lookups made using the attribute access syntax ' + '– directly\n' + ' accessing the module globals (whether by code within ' + 'the module, or\n' + ' via a reference to the module’s globals dictionary) is ' + 'unaffected.\n' + '\n' + 'Changed in version 3.5: "__class__" module attribute is ' + 'now writable.\n' + '\n' + 'Added in version 3.7: "__getattr__" and "__dir__" module ' + 'attributes.\n' + '\n' + 'See also:\n' + '\n' + ' **PEP 562** - Module __getattr__ and __dir__\n' + ' Describes the "__getattr__" and "__dir__" functions ' + 'on modules.\n' + '\n' + '\n' + 'Implementing Descriptors\n' + '========================\n' + '\n' + 'The following methods only apply when an instance of the ' + 'class\n' + 'containing the method (a so-called *descriptor* class) ' + 'appears in an\n' + '*owner* class (the descriptor must be in either the ' + 'owner’s class\n' + 'dictionary or in the class dictionary for one of its ' + 'parents). In the\n' + 'examples below, “the attribute” refers to the attribute ' + 'whose name is\n' + 'the key of the property in the owner class’ "__dict__". ' + 'The "object"\n' + 'class itself does not implement any of these protocols.\n' + '\n' + 'object.__get__(self, instance, owner=None)\n' + '\n' + ' Called to get the attribute of the owner class (class ' + 'attribute\n' + ' access) or of an instance of that class (instance ' + 'attribute\n' + ' access). The optional *owner* argument is the owner ' + 'class, while\n' + ' *instance* is the instance that the attribute was ' + 'accessed through,\n' + ' or "None" when the attribute is accessed through the ' + '*owner*.\n' + '\n' + ' This method should return the computed attribute ' + 'value or raise an\n' + ' "AttributeError" exception.\n' + '\n' + ' **PEP 252** specifies that "__get__()" is callable ' + 'with one or two\n' + ' arguments. Python’s own built-in descriptors support ' + 'this\n' + ' specification; however, it is likely that some ' + 'third-party tools\n' + ' have descriptors that require both arguments. ' + 'Python’s own\n' + ' "__getattribute__()" implementation always passes in ' + 'both arguments\n' + ' whether they are required or not.\n' + '\n' + 'object.__set__(self, instance, value)\n' + '\n' + ' Called to set the attribute on an instance *instance* ' + 'of the owner\n' + ' class to a new value, *value*.\n' + '\n' + ' Note, adding "__set__()" or "__delete__()" changes ' + 'the kind of\n' + ' descriptor to a “data descriptor”. See Invoking ' + 'Descriptors for\n' + ' more details.\n' + '\n' + 'object.__delete__(self, instance)\n' + '\n' + ' Called to delete the attribute on an instance ' + '*instance* of the\n' + ' owner class.\n' + '\n' + 'Instances of descriptors may also have the ' + '"__objclass__" attribute\n' + 'present:\n' + '\n' + 'object.__objclass__\n' + '\n' + ' The attribute "__objclass__" is interpreted by the ' + '"inspect" module\n' + ' as specifying the class where this object was defined ' + '(setting this\n' + ' appropriately can assist in runtime introspection of ' + 'dynamic class\n' + ' attributes). For callables, it may indicate that an ' + 'instance of the\n' + ' given type (or a subclass) is expected or required as ' + 'the first\n' + ' positional argument (for example, CPython sets this ' + 'attribute for\n' + ' unbound methods that are implemented in C).\n' + '\n' + '\n' + 'Invoking Descriptors\n' + '====================\n' + '\n' + 'In general, a descriptor is an object attribute with ' + '“binding\n' + 'behavior”, one whose attribute access has been ' + 'overridden by methods\n' + 'in the descriptor protocol: "__get__()", "__set__()", ' + 'and\n' + '"__delete__()". If any of those methods are defined for ' + 'an object, it\n' + 'is said to be a descriptor.\n' + '\n' + 'The default behavior for attribute access is to get, ' + 'set, or delete\n' + 'the attribute from an object’s dictionary. For instance, ' + '"a.x" has a\n' + 'lookup chain starting with "a.__dict__[\'x\']", then\n' + '"type(a).__dict__[\'x\']", and continuing through the ' + 'base classes of\n' + '"type(a)" excluding metaclasses.\n' + '\n' + 'However, if the looked-up value is an object defining ' + 'one of the\n' + 'descriptor methods, then Python may override the default ' + 'behavior and\n' + 'invoke the descriptor method instead. Where this occurs ' + 'in the\n' + 'precedence chain depends on which descriptor methods ' + 'were defined and\n' + 'how they were called.\n' + '\n' + 'The starting point for descriptor invocation is a ' + 'binding, "a.x". How\n' + 'the arguments are assembled depends on "a":\n' + '\n' + 'Direct Call\n' + ' The simplest and least common call is when user code ' + 'directly\n' + ' invokes a descriptor method: "x.__get__(a)".\n' + '\n' + 'Instance Binding\n' + ' If binding to an object instance, "a.x" is ' + 'transformed into the\n' + ' call: "type(a).__dict__[\'x\'].__get__(a, type(a))".\n' + '\n' + 'Class Binding\n' + ' If binding to a class, "A.x" is transformed into the ' + 'call:\n' + ' "A.__dict__[\'x\'].__get__(None, A)".\n' + '\n' + 'Super Binding\n' + ' A dotted lookup such as "super(A, a).x" searches\n' + ' "a.__class__.__mro__" for a base class "B" following ' + '"A" and then\n' + ' returns "B.__dict__[\'x\'].__get__(a, A)". If not a ' + 'descriptor, "x"\n' + ' is returned unchanged.\n' + '\n' + 'For instance bindings, the precedence of descriptor ' + 'invocation depends\n' + 'on which descriptor methods are defined. A descriptor ' + 'can define any\n' + 'combination of "__get__()", "__set__()" and ' + '"__delete__()". If it\n' + 'does not define "__get__()", then accessing the ' + 'attribute will return\n' + 'the descriptor object itself unless there is a value in ' + 'the object’s\n' + 'instance dictionary. If the descriptor defines ' + '"__set__()" and/or\n' + '"__delete__()", it is a data descriptor; if it defines ' + 'neither, it is\n' + 'a non-data descriptor. Normally, data descriptors ' + 'define both\n' + '"__get__()" and "__set__()", while non-data descriptors ' + 'have just the\n' + '"__get__()" method. Data descriptors with "__get__()" ' + 'and "__set__()"\n' + '(and/or "__delete__()") defined always override a ' + 'redefinition in an\n' + 'instance dictionary. In contrast, non-data descriptors ' + 'can be\n' + 'overridden by instances.\n' + '\n' + 'Python methods (including those decorated with ' + '"@staticmethod" and\n' + '"@classmethod") are implemented as non-data ' + 'descriptors. Accordingly,\n' + 'instances can redefine and override methods. This ' + 'allows individual\n' + 'instances to acquire behaviors that differ from other ' + 'instances of the\n' + 'same class.\n' + '\n' + 'The "property()" function is implemented as a data ' + 'descriptor.\n' + 'Accordingly, instances cannot override the behavior of a ' + 'property.\n' + '\n' + '\n' + '__slots__\n' + '=========\n' + '\n' + '*__slots__* allow us to explicitly declare data members ' + '(like\n' + 'properties) and deny the creation of "__dict__" and ' + '*__weakref__*\n' + '(unless explicitly declared in *__slots__* or available ' + 'in a parent.)\n' + '\n' + 'The space saved over using "__dict__" can be ' + 'significant. Attribute\n' + 'lookup speed can be significantly improved as well.\n' + '\n' + 'object.__slots__\n' + '\n' + ' This class variable can be assigned a string, ' + 'iterable, or sequence\n' + ' of strings with variable names used by instances. ' + '*__slots__*\n' + ' reserves space for the declared variables and ' + 'prevents the\n' + ' automatic creation of "__dict__" and *__weakref__* ' + 'for each\n' + ' instance.\n' + '\n' + 'Notes on using *__slots__*:\n' + '\n' + '* When inheriting from a class without *__slots__*, the ' + '"__dict__" and\n' + ' *__weakref__* attribute of the instances will always ' + 'be accessible.\n' + '\n' + '* Without a "__dict__" variable, instances cannot be ' + 'assigned new\n' + ' variables not listed in the *__slots__* definition. ' + 'Attempts to\n' + ' assign to an unlisted variable name raises ' + '"AttributeError". If\n' + ' dynamic assignment of new variables is desired, then ' + 'add\n' + ' "\'__dict__\'" to the sequence of strings in the ' + '*__slots__*\n' + ' declaration.\n' + '\n' + '* Without a *__weakref__* variable for each instance, ' + 'classes defining\n' + ' *__slots__* do not support "weak references" to its ' + 'instances. If\n' + ' weak reference support is needed, then add ' + '"\'__weakref__\'" to the\n' + ' sequence of strings in the *__slots__* declaration.\n' + '\n' + '* *__slots__* are implemented at the class level by ' + 'creating\n' + ' descriptors for each variable name. As a result, ' + 'class attributes\n' + ' cannot be used to set default values for instance ' + 'variables defined\n' + ' by *__slots__*; otherwise, the class attribute would ' + 'overwrite the\n' + ' descriptor assignment.\n' + '\n' + '* The action of a *__slots__* declaration is not limited ' + 'to the class\n' + ' where it is defined. *__slots__* declared in parents ' + 'are available\n' + ' in child classes. However, instances of a child ' + 'subclass will get a\n' + ' "__dict__" and *__weakref__* unless the subclass also ' + 'defines\n' + ' *__slots__* (which should only contain names of any ' + '*additional*\n' + ' slots).\n' + '\n' + '* If a class defines a slot also defined in a base ' + 'class, the instance\n' + ' variable defined by the base class slot is ' + 'inaccessible (except by\n' + ' retrieving its descriptor directly from the base ' + 'class). This\n' + ' renders the meaning of the program undefined. In the ' + 'future, a\n' + ' check may be added to prevent this.\n' + '\n' + '* "TypeError" will be raised if nonempty *__slots__* are ' + 'defined for a\n' + ' class derived from a ""variable-length" built-in type" ' + 'such as\n' + ' "int", "bytes", and "tuple".\n' + '\n' + '* Any non-string *iterable* may be assigned to ' + '*__slots__*.\n' + '\n' + '* If a "dictionary" is used to assign *__slots__*, the ' + 'dictionary keys\n' + ' will be used as the slot names. The values of the ' + 'dictionary can be\n' + ' used to provide per-attribute docstrings that will be ' + 'recognised by\n' + ' "inspect.getdoc()" and displayed in the output of ' + '"help()".\n' + '\n' + '* "__class__" assignment works only if both classes have ' + 'the same\n' + ' *__slots__*.\n' + '\n' + '* Multiple inheritance with multiple slotted parent ' + 'classes can be\n' + ' used, but only one parent is allowed to have ' + 'attributes created by\n' + ' slots (the other bases must have empty slot layouts) - ' + 'violations\n' + ' raise "TypeError".\n' + '\n' + '* If an *iterator* is used for *__slots__* then a ' + '*descriptor* is\n' + ' created for each of the iterator’s values. However, ' + 'the *__slots__*\n' + ' attribute will be an empty iterator.\n', + 'attribute-references': 'Attribute references\n' + '********************\n' + '\n' + 'An attribute reference is a primary followed by a ' + 'period and a name:\n' + '\n' + ' attributeref ::= primary "." identifier\n' + '\n' + 'The primary must evaluate to an object of a type ' + 'that supports\n' + 'attribute references, which most objects do. This ' + 'object is then\n' + 'asked to produce the attribute whose name is the ' + 'identifier. The type\n' + 'and value produced is determined by the object. ' + 'Multiple evaluations\n' + 'of the same attribute reference may yield different ' + 'objects.\n' + '\n' + 'This production can be customized by overriding the\n' + '"__getattribute__()" method or the "__getattr__()" ' + 'method. The\n' + '"__getattribute__()" method is called first and ' + 'either returns a value\n' + 'or raises "AttributeError" if the attribute is not ' + 'available.\n' + '\n' + 'If an "AttributeError" is raised and the object has ' + 'a "__getattr__()"\n' + 'method, that method is called as a fallback.\n', + 'augassign': 'Augmented assignment statements\n' + '*******************************\n' '\n' - 'Code objects are used by the implementation to ' - 'represent “pseudo-\n' - 'compiled” executable Python code such as a function ' - 'body. They differ\n' - 'from function objects because they don’t contain a ' - 'reference to their\n' - 'global execution environment. Code objects are ' - 'returned by the built-\n' - 'in "compile()" function and can be extracted from ' - 'function objects\n' - 'through their "__code__" attribute. See also the ' - '"code" module.\n' + 'Augmented assignment is the combination, in a single statement, ' + 'of a\n' + 'binary operation and an assignment statement:\n' '\n' - 'A code object can be executed or evaluated by passing ' - 'it (instead of a\n' - 'source string) to the "exec()" or "eval()" built-in ' - 'functions.\n' + ' augmented_assignment_stmt ::= augtarget augop ' + '(expression_list | yield_expression)\n' + ' augtarget ::= identifier | attributeref | ' + 'subscription | slicing\n' + ' augop ::= "+=" | "-=" | "*=" | "@=" | ' + '"/=" | "//=" | "%=" | "**="\n' + ' | ">>=" | "<<=" | "&=" | "^=" | "|="\n' '\n' - 'See The standard type hierarchy for more ' - 'information.\n', - 'bltin-ellipsis-object': 'The Ellipsis Object\n' - '*******************\n' - '\n' - 'This object is commonly used by slicing (see ' - 'Slicings). It supports\n' - 'no special operations. There is exactly one ' - 'ellipsis object, named\n' - '"Ellipsis" (a built-in name). "type(Ellipsis)()" ' - 'produces the\n' - '"Ellipsis" singleton.\n' - '\n' - 'It is written as "Ellipsis" or "...".\n', - 'bltin-null-object': 'The Null Object\n' - '***************\n' - '\n' - 'This object is returned by functions that don’t ' - 'explicitly return a\n' - 'value. It supports no special operations. There is ' - 'exactly one null\n' - 'object, named "None" (a built-in name). "type(None)()" ' - 'produces the\n' - 'same singleton.\n' - '\n' - 'It is written as "None".\n', - 'bltin-type-objects': 'Type Objects\n' - '************\n' + '(See section Primaries for the syntax definitions of the last ' + 'three\n' + 'symbols.)\n' '\n' - 'Type objects represent the various object types. An ' - 'object’s type is\n' - 'accessed by the built-in function "type()". There are ' - 'no special\n' - 'operations on types. The standard module "types" ' - 'defines names for\n' - 'all standard built-in types.\n' + 'An augmented assignment evaluates the target (which, unlike ' + 'normal\n' + 'assignment statements, cannot be an unpacking) and the ' + 'expression\n' + 'list, performs the binary operation specific to the type of ' + 'assignment\n' + 'on the two operands, and assigns the result to the original ' + 'target.\n' + 'The target is only evaluated once.\n' '\n' - 'Types are written like this: "".\n', - 'booleans': 'Boolean operations\n' - '******************\n' - '\n' - ' or_test ::= and_test | or_test "or" and_test\n' - ' and_test ::= not_test | and_test "and" not_test\n' - ' not_test ::= comparison | "not" not_test\n' - '\n' - 'In the context of Boolean operations, and also when expressions ' - 'are\n' - 'used by control flow statements, the following values are ' - 'interpreted\n' - 'as false: "False", "None", numeric zero of all types, and empty\n' - 'strings and containers (including strings, tuples, lists,\n' - 'dictionaries, sets and frozensets). All other values are ' - 'interpreted\n' - 'as true. User-defined objects can customize their truth value ' - 'by\n' - 'providing a "__bool__()" method.\n' - '\n' - 'The operator "not" yields "True" if its argument is false, ' - '"False"\n' - 'otherwise.\n' - '\n' - 'The expression "x and y" first evaluates *x*; if *x* is false, ' - 'its\n' - 'value is returned; otherwise, *y* is evaluated and the resulting ' - 'value\n' - 'is returned.\n' - '\n' - 'The expression "x or y" first evaluates *x*; if *x* is true, its ' - 'value\n' - 'is returned; otherwise, *y* is evaluated and the resulting value ' - 'is\n' - 'returned.\n' - '\n' - 'Note that neither "and" nor "or" restrict the value and type ' - 'they\n' - 'return to "False" and "True", but rather return the last ' - 'evaluated\n' - 'argument. This is sometimes useful, e.g., if "s" is a string ' - 'that\n' - 'should be replaced by a default value if it is empty, the ' - 'expression\n' - '"s or \'foo\'" yields the desired value. Because "not" has to ' - 'create a\n' - 'new value, it returns a boolean value regardless of the type of ' - 'its\n' - 'argument (for example, "not \'foo\'" produces "False" rather ' - 'than "\'\'".)\n', - 'break': 'The "break" statement\n' - '*********************\n' - '\n' - ' break_stmt ::= "break"\n' - '\n' - '"break" may only occur syntactically nested in a "for" or "while"\n' - 'loop, but not nested in a function or class definition within that\n' - 'loop.\n' - '\n' - 'It terminates the nearest enclosing loop, skipping the optional ' - '"else"\n' - 'clause if the loop has one.\n' - '\n' - 'If a "for" loop is terminated by "break", the loop control target\n' - 'keeps its current value.\n' - '\n' - 'When "break" passes control out of a "try" statement with a ' - '"finally"\n' - 'clause, that "finally" clause is executed before really leaving ' - 'the\n' - 'loop.\n', - 'callable-types': 'Emulating callable objects\n' - '**************************\n' - '\n' - 'object.__call__(self[, args...])\n' - '\n' - ' Called when the instance is “called” as a function; if ' - 'this method\n' - ' is defined, "x(arg1, arg2, ...)" is a shorthand for\n' - ' "x.__call__(arg1, arg2, ...)".\n', - 'calls': 'Calls\n' - '*****\n' - '\n' - 'A call calls a callable object (e.g., a *function*) with a ' - 'possibly\n' - 'empty series of *arguments*:\n' - '\n' - ' call ::= primary "(" [argument_list [","] | ' - 'comprehension] ")"\n' - ' argument_list ::= positional_arguments ["," ' - 'starred_and_keywords]\n' - ' ["," keywords_arguments]\n' - ' | starred_and_keywords ["," ' - 'keywords_arguments]\n' - ' | keywords_arguments\n' - ' positional_arguments ::= ["*"] expression ("," ["*"] ' - 'expression)*\n' - ' starred_and_keywords ::= ("*" expression | keyword_item)\n' - ' ("," "*" expression | "," ' - 'keyword_item)*\n' - ' keywords_arguments ::= (keyword_item | "**" expression)\n' - ' ("," keyword_item | "," "**" ' - 'expression)*\n' - ' keyword_item ::= identifier "=" expression\n' - '\n' - 'An optional trailing comma may be present after the positional and\n' - 'keyword arguments but does not affect the semantics.\n' - '\n' - 'The primary must evaluate to a callable object (user-defined\n' - 'functions, built-in functions, methods of built-in objects, class\n' - 'objects, methods of class instances, and all objects having a\n' - '"__call__()" method are callable). All argument expressions are\n' - 'evaluated before the call is attempted. Please refer to section\n' - 'Function definitions for the syntax of formal *parameter* lists.\n' - '\n' - 'If keyword arguments are present, they are first converted to\n' - 'positional arguments, as follows. First, a list of unfilled slots ' - 'is\n' - 'created for the formal parameters. If there are N positional\n' - 'arguments, they are placed in the first N slots. Next, for each\n' - 'keyword argument, the identifier is used to determine the\n' - 'corresponding slot (if the identifier is the same as the first ' - 'formal\n' - 'parameter name, the first slot is used, and so on). If the slot ' - 'is\n' - 'already filled, a "TypeError" exception is raised. Otherwise, the\n' - 'value of the argument is placed in the slot, filling it (even if ' - 'the\n' - 'expression is "None", it fills the slot). When all arguments have\n' - 'been processed, the slots that are still unfilled are filled with ' - 'the\n' - 'corresponding default value from the function definition. ' - '(Default\n' - 'values are calculated, once, when the function is defined; thus, a\n' - 'mutable object such as a list or dictionary used as default value ' - 'will\n' - 'be shared by all calls that don’t specify an argument value for ' - 'the\n' - 'corresponding slot; this should usually be avoided.) If there are ' - 'any\n' - 'unfilled slots for which no default value is specified, a ' - '"TypeError"\n' - 'exception is raised. Otherwise, the list of filled slots is used ' - 'as\n' - 'the argument list for the call.\n' - '\n' - '**CPython implementation detail:** An implementation may provide\n' - 'built-in functions whose positional parameters do not have names, ' - 'even\n' - 'if they are ‘named’ for the purpose of documentation, and which\n' - 'therefore cannot be supplied by keyword. In CPython, this is the ' - 'case\n' - 'for functions implemented in C that use "PyArg_ParseTuple()" to ' - 'parse\n' - 'their arguments.\n' - '\n' - 'If there are more positional arguments than there are formal ' - 'parameter\n' - 'slots, a "TypeError" exception is raised, unless a formal ' - 'parameter\n' - 'using the syntax "*identifier" is present; in this case, that ' - 'formal\n' - 'parameter receives a tuple containing the excess positional ' - 'arguments\n' - '(or an empty tuple if there were no excess positional arguments).\n' - '\n' - 'If any keyword argument does not correspond to a formal parameter\n' - 'name, a "TypeError" exception is raised, unless a formal parameter\n' - 'using the syntax "**identifier" is present; in this case, that ' - 'formal\n' - 'parameter receives a dictionary containing the excess keyword\n' - 'arguments (using the keywords as keys and the argument values as\n' - 'corresponding values), or a (new) empty dictionary if there were ' - 'no\n' - 'excess keyword arguments.\n' - '\n' - 'If the syntax "*expression" appears in the function call, ' - '"expression"\n' - 'must evaluate to an *iterable*. Elements from these iterables are\n' - 'treated as if they were additional positional arguments. For the ' - 'call\n' - '"f(x1, x2, *y, x3, x4)", if *y* evaluates to a sequence *y1*, …, ' - '*yM*,\n' - 'this is equivalent to a call with M+4 positional arguments *x1*, ' - '*x2*,\n' - '*y1*, …, *yM*, *x3*, *x4*.\n' - '\n' - 'A consequence of this is that although the "*expression" syntax ' - 'may\n' - 'appear *after* explicit keyword arguments, it is processed ' - '*before*\n' - 'the keyword arguments (and any "**expression" arguments – see ' - 'below).\n' - 'So:\n' - '\n' - ' >>> def f(a, b):\n' - ' ... print(a, b)\n' - ' ...\n' - ' >>> f(b=1, *(2,))\n' - ' 2 1\n' - ' >>> f(a=1, *(2,))\n' - ' Traceback (most recent call last):\n' - ' File "", line 1, in \n' - " TypeError: f() got multiple values for keyword argument 'a'\n" - ' >>> f(1, *(2,))\n' - ' 1 2\n' - '\n' - 'It is unusual for both keyword arguments and the "*expression" ' - 'syntax\n' - 'to be used in the same call, so in practice this confusion does ' - 'not\n' - 'arise.\n' - '\n' - 'If the syntax "**expression" appears in the function call,\n' - '"expression" must evaluate to a *mapping*, the contents of which ' - 'are\n' - 'treated as additional keyword arguments. If a keyword is already\n' - 'present (as an explicit keyword argument, or from another ' - 'unpacking),\n' - 'a "TypeError" exception is raised.\n' - '\n' - 'Formal parameters using the syntax "*identifier" or "**identifier"\n' - 'cannot be used as positional argument slots or as keyword argument\n' - 'names.\n' - '\n' - 'Changed in version 3.5: Function calls accept any number of "*" ' - 'and\n' - '"**" unpackings, positional arguments may follow iterable ' - 'unpackings\n' - '("*"), and keyword arguments may follow dictionary unpackings ' - '("**").\n' - 'Originally proposed by **PEP 448**.\n' - '\n' - 'A call always returns some value, possibly "None", unless it raises ' - 'an\n' - 'exception. How this value is computed depends on the type of the\n' - 'callable object.\n' - '\n' - 'If it is—\n' - '\n' - 'a user-defined function:\n' - ' The code block for the function is executed, passing it the\n' - ' argument list. The first thing the code block will do is bind ' - 'the\n' - ' formal parameters to the arguments; this is described in ' - 'section\n' - ' Function definitions. When the code block executes a "return"\n' - ' statement, this specifies the return value of the function ' - 'call.\n' - '\n' - 'a built-in function or method:\n' - ' The result is up to the interpreter; see Built-in Functions for ' - 'the\n' - ' descriptions of built-in functions and methods.\n' - '\n' - 'a class object:\n' - ' A new instance of that class is returned.\n' - '\n' - 'a class instance method:\n' - ' The corresponding user-defined function is called, with an ' - 'argument\n' - ' list that is one longer than the argument list of the call: the\n' - ' instance becomes the first argument.\n' - '\n' - 'a class instance:\n' - ' The class must define a "__call__()" method; the effect is then ' - 'the\n' - ' same as if that method was called.\n', - 'class': 'Class definitions\n' - '*****************\n' - '\n' - 'A class definition defines a class object (see section The ' - 'standard\n' - 'type hierarchy):\n' - '\n' - ' classdef ::= [decorators] "class" classname [inheritance] ":" ' - 'suite\n' - ' inheritance ::= "(" [argument_list] ")"\n' - ' classname ::= identifier\n' - '\n' - 'A class definition is an executable statement. The inheritance ' - 'list\n' - 'usually gives a list of base classes (see Metaclasses for more\n' - 'advanced uses), so each item in the list should evaluate to a ' - 'class\n' - 'object which allows subclassing. Classes without an inheritance ' - 'list\n' - 'inherit, by default, from the base class "object"; hence,\n' - '\n' - ' class Foo:\n' - ' pass\n' - '\n' - 'is equivalent to\n' - '\n' - ' class Foo(object):\n' - ' pass\n' - '\n' - 'The class’s suite is then executed in a new execution frame (see\n' - 'Naming and binding), using a newly created local namespace and the\n' - 'original global namespace. (Usually, the suite contains mostly\n' - 'function definitions.) When the class’s suite finishes execution, ' - 'its\n' - 'execution frame is discarded but its local namespace is saved. [3] ' - 'A\n' - 'class object is then created using the inheritance list for the ' - 'base\n' - 'classes and the saved local namespace for the attribute ' - 'dictionary.\n' - 'The class name is bound to this class object in the original local\n' - 'namespace.\n' - '\n' - 'The order in which attributes are defined in the class body is\n' - 'preserved in the new class’s "__dict__". Note that this is ' - 'reliable\n' - 'only right after the class is created and only for classes that ' - 'were\n' - 'defined using the definition syntax.\n' - '\n' - 'Class creation can be customized heavily using metaclasses.\n' - '\n' - 'Classes can also be decorated: just like when decorating ' - 'functions,\n' - '\n' - ' @f1(arg)\n' - ' @f2\n' - ' class Foo: pass\n' - '\n' - 'is roughly equivalent to\n' - '\n' - ' class Foo: pass\n' - ' Foo = f1(arg)(f2(Foo))\n' - '\n' - 'The evaluation rules for the decorator expressions are the same as ' - 'for\n' - 'function decorators. The result is then bound to the class name.\n' - '\n' - '**Programmer’s note:** Variables defined in the class definition ' - 'are\n' - 'class attributes; they are shared by instances. Instance ' - 'attributes\n' - 'can be set in a method with "self.name = value". Both class and\n' - 'instance attributes are accessible through the notation ' - '“"self.name"”,\n' - 'and an instance attribute hides a class attribute with the same ' - 'name\n' - 'when accessed in this way. Class attributes can be used as ' - 'defaults\n' - 'for instance attributes, but using mutable values there can lead ' - 'to\n' - 'unexpected results. Descriptors can be used to create instance\n' - 'variables with different implementation details.\n' - '\n' - 'See also:\n' - '\n' - ' **PEP 3115** - Metaclasses in Python 3000\n' - ' The proposal that changed the declaration of metaclasses to ' - 'the\n' - ' current syntax, and the semantics for how classes with\n' - ' metaclasses are constructed.\n' - '\n' - ' **PEP 3129** - Class Decorators\n' - ' The proposal that added class decorators. Function and ' - 'method\n' - ' decorators were introduced in **PEP 318**.\n', - 'comparisons': 'Comparisons\n' - '***********\n' - '\n' - 'Unlike C, all comparison operations in Python have the same ' - 'priority,\n' - 'which is lower than that of any arithmetic, shifting or ' - 'bitwise\n' - 'operation. Also unlike C, expressions like "a < b < c" have ' - 'the\n' - 'interpretation that is conventional in mathematics:\n' - '\n' - ' comparison ::= or_expr (comp_operator or_expr)*\n' - ' comp_operator ::= "<" | ">" | "==" | ">=" | "<=" | "!="\n' - ' | "is" ["not"] | ["not"] "in"\n' - '\n' - 'Comparisons yield boolean values: "True" or "False".\n' - '\n' - 'Comparisons can be chained arbitrarily, e.g., "x < y <= z" ' - 'is\n' - 'equivalent to "x < y and y <= z", except that "y" is ' - 'evaluated only\n' - 'once (but in both cases "z" is not evaluated at all when "x < ' - 'y" is\n' - 'found to be false).\n' - '\n' - 'Formally, if *a*, *b*, *c*, …, *y*, *z* are expressions and ' - '*op1*,\n' - '*op2*, …, *opN* are comparison operators, then "a op1 b op2 c ' - '... y\n' - 'opN z" is equivalent to "a op1 b and b op2 c and ... y opN ' - 'z", except\n' - 'that each expression is evaluated at most once.\n' - '\n' - 'Note that "a op1 b op2 c" doesn’t imply any kind of ' - 'comparison between\n' - '*a* and *c*, so that, e.g., "x < y > z" is perfectly legal ' - '(though\n' - 'perhaps not pretty).\n' - '\n' - '\n' - 'Value comparisons\n' - '=================\n' - '\n' - 'The operators "<", ">", "==", ">=", "<=", and "!=" compare ' - 'the values\n' - 'of two objects. The objects do not need to have the same ' - 'type.\n' - '\n' - 'Chapter Objects, values and types states that objects have a ' - 'value (in\n' - 'addition to type and identity). The value of an object is a ' - 'rather\n' - 'abstract notion in Python: For example, there is no canonical ' - 'access\n' - 'method for an object’s value. Also, there is no requirement ' - 'that the\n' - 'value of an object should be constructed in a particular way, ' - 'e.g.\n' - 'comprised of all its data attributes. Comparison operators ' - 'implement a\n' - 'particular notion of what the value of an object is. One can ' - 'think of\n' - 'them as defining the value of an object indirectly, by means ' - 'of their\n' - 'comparison implementation.\n' - '\n' - 'Because all types are (direct or indirect) subtypes of ' - '"object", they\n' - 'inherit the default comparison behavior from "object". Types ' - 'can\n' - 'customize their comparison behavior by implementing *rich ' - 'comparison\n' - 'methods* like "__lt__()", described in Basic customization.\n' - '\n' - 'The default behavior for equality comparison ("==" and "!=") ' - 'is based\n' - 'on the identity of the objects. Hence, equality comparison ' - 'of\n' - 'instances with the same identity results in equality, and ' - 'equality\n' - 'comparison of instances with different identities results in\n' - 'inequality. A motivation for this default behavior is the ' - 'desire that\n' - 'all objects should be reflexive (i.e. "x is y" implies "x == ' - 'y").\n' - '\n' - 'A default order comparison ("<", ">", "<=", and ">=") is not ' - 'provided;\n' - 'an attempt raises "TypeError". A motivation for this default ' - 'behavior\n' - 'is the lack of a similar invariant as for equality.\n' - '\n' - 'The behavior of the default equality comparison, that ' - 'instances with\n' - 'different identities are always unequal, may be in contrast ' - 'to what\n' - 'types will need that have a sensible definition of object ' - 'value and\n' - 'value-based equality. Such types will need to customize ' - 'their\n' - 'comparison behavior, and in fact, a number of built-in types ' - 'have done\n' - 'that.\n' - '\n' - 'The following list describes the comparison behavior of the ' - 'most\n' - 'important built-in types.\n' - '\n' - '* Numbers of built-in numeric types (Numeric Types — int, ' - 'float,\n' - ' complex) and of the standard library types ' - '"fractions.Fraction" and\n' - ' "decimal.Decimal" can be compared within and across their ' - 'types,\n' - ' with the restriction that complex numbers do not support ' - 'order\n' - ' comparison. Within the limits of the types involved, they ' - 'compare\n' - ' mathematically (algorithmically) correct without loss of ' - 'precision.\n' - '\n' - ' The not-a-number values "float(\'NaN\')" and ' - '"Decimal(\'NaN\')" are\n' - ' special. They are identical to themselves ("x is x" is ' - 'true) but\n' - ' are not equal to themselves ("x == x" is false). ' - 'Additionally,\n' - ' comparing any number to a not-a-number value will return ' - '"False".\n' - ' For example, both "3 < float(\'NaN\')" and "float(\'NaN\') ' - '< 3" will\n' - ' return "False".\n' - '\n' - '* Binary sequences (instances of "bytes" or "bytearray") can ' - 'be\n' - ' compared within and across their types. They compare\n' - ' lexicographically using the numeric values of their ' - 'elements.\n' - '\n' - '* Strings (instances of "str") compare lexicographically ' - 'using the\n' - ' numerical Unicode code points (the result of the built-in ' - 'function\n' - ' "ord()") of their characters. [3]\n' - '\n' - ' Strings and binary sequences cannot be directly compared.\n' - '\n' - '* Sequences (instances of "tuple", "list", or "range") can ' - 'be\n' - ' compared only within each of their types, with the ' - 'restriction that\n' - ' ranges do not support order comparison. Equality ' - 'comparison across\n' - ' these types results in inequality, and ordering comparison ' - 'across\n' - ' these types raises "TypeError".\n' - '\n' - ' Sequences compare lexicographically using comparison of\n' - ' corresponding elements, whereby reflexivity of the elements ' - 'is\n' - ' enforced.\n' - '\n' - ' In enforcing reflexivity of elements, the comparison of ' - 'collections\n' - ' assumes that for a collection element "x", "x == x" is ' - 'always true.\n' - ' Based on that assumption, element identity is compared ' - 'first, and\n' - ' element comparison is performed only for distinct ' - 'elements. This\n' - ' approach yields the same result as a strict element ' - 'comparison\n' - ' would, if the compared elements are reflexive. For ' - 'non-reflexive\n' - ' elements, the result is different than for strict element\n' - ' comparison, and may be surprising: The non-reflexive ' - 'not-a-number\n' - ' values for example result in the following comparison ' - 'behavior when\n' - ' used in a list:\n' - '\n' - " >>> nan = float('NaN')\n" - ' >>> nan is nan\n' - ' True\n' - ' >>> nan == nan\n' - ' False <-- the defined non-reflexive ' - 'behavior of NaN\n' - ' >>> [nan] == [nan]\n' - ' True <-- list enforces reflexivity and ' - 'tests identity first\n' - '\n' - ' Lexicographical comparison between built-in collections ' - 'works as\n' - ' follows:\n' - '\n' - ' * For two collections to compare equal, they must be of the ' - 'same\n' - ' type, have the same length, and each pair of ' - 'corresponding\n' - ' elements must compare equal (for example, "[1,2] == ' - '(1,2)" is\n' - ' false because the type is not the same).\n' - '\n' - ' * Collections that support order comparison are ordered the ' - 'same\n' - ' as their first unequal elements (for example, "[1,2,x] <= ' - '[1,2,y]"\n' - ' has the same value as "x <= y"). If a corresponding ' - 'element does\n' - ' not exist, the shorter collection is ordered first (for ' - 'example,\n' - ' "[1,2] < [1,2,3]" is true).\n' - '\n' - '* Mappings (instances of "dict") compare equal if and only if ' - 'they\n' - ' have equal *(key, value)* pairs. Equality comparison of the ' - 'keys and\n' - ' values enforces reflexivity.\n' - '\n' - ' Order comparisons ("<", ">", "<=", and ">=") raise ' - '"TypeError".\n' - '\n' - '* Sets (instances of "set" or "frozenset") can be compared ' - 'within\n' - ' and across their types.\n' - '\n' - ' They define order comparison operators to mean subset and ' - 'superset\n' - ' tests. Those relations do not define total orderings (for ' - 'example,\n' - ' the two sets "{1,2}" and "{2,3}" are not equal, nor subsets ' - 'of one\n' - ' another, nor supersets of one another). Accordingly, sets ' - 'are not\n' - ' appropriate arguments for functions which depend on total ' - 'ordering\n' - ' (for example, "min()", "max()", and "sorted()" produce ' - 'undefined\n' - ' results given a list of sets as inputs).\n' - '\n' - ' Comparison of sets enforces reflexivity of its elements.\n' - '\n' - '* Most other built-in types have no comparison methods ' - 'implemented,\n' - ' so they inherit the default comparison behavior.\n' - '\n' - 'User-defined classes that customize their comparison behavior ' - 'should\n' - 'follow some consistency rules, if possible:\n' - '\n' - '* Equality comparison should be reflexive. In other words, ' - 'identical\n' - ' objects should compare equal:\n' - '\n' - ' "x is y" implies "x == y"\n' - '\n' - '* Comparison should be symmetric. In other words, the ' - 'following\n' - ' expressions should have the same result:\n' - '\n' - ' "x == y" and "y == x"\n' - '\n' - ' "x != y" and "y != x"\n' - '\n' - ' "x < y" and "y > x"\n' - '\n' - ' "x <= y" and "y >= x"\n' - '\n' - '* Comparison should be transitive. The following ' - '(non-exhaustive)\n' - ' examples illustrate that:\n' - '\n' - ' "x > y and y > z" implies "x > z"\n' - '\n' - ' "x < y and y <= z" implies "x < z"\n' - '\n' - '* Inverse comparison should result in the boolean negation. ' - 'In other\n' - ' words, the following expressions should have the same ' - 'result:\n' - '\n' - ' "x == y" and "not x != y"\n' - '\n' - ' "x < y" and "not x >= y" (for total ordering)\n' - '\n' - ' "x > y" and "not x <= y" (for total ordering)\n' - '\n' - ' The last two expressions apply to totally ordered ' - 'collections (e.g.\n' - ' to sequences, but not to sets or mappings). See also the\n' - ' "total_ordering()" decorator.\n' - '\n' - '* The "hash()" result should be consistent with equality. ' - 'Objects\n' - ' that are equal should either have the same hash value, or ' - 'be marked\n' - ' as unhashable.\n' - '\n' - 'Python does not enforce these consistency rules. In fact, ' - 'the\n' - 'not-a-number values are an example for not following these ' - 'rules.\n' - '\n' - '\n' - 'Membership test operations\n' - '==========================\n' - '\n' - 'The operators "in" and "not in" test for membership. "x in ' - 's"\n' - 'evaluates to "True" if *x* is a member of *s*, and "False" ' - 'otherwise.\n' - '"x not in s" returns the negation of "x in s". All built-in ' - 'sequences\n' - 'and set types support this as well as dictionary, for which ' - '"in" tests\n' - 'whether the dictionary has a given key. For container types ' - 'such as\n' - 'list, tuple, set, frozenset, dict, or collections.deque, the\n' - 'expression "x in y" is equivalent to "any(x is e or x == e ' - 'for e in\n' - 'y)".\n' - '\n' - 'For the string and bytes types, "x in y" is "True" if and ' - 'only if *x*\n' - 'is a substring of *y*. An equivalent test is "y.find(x) != ' - '-1".\n' - 'Empty strings are always considered to be a substring of any ' - 'other\n' - 'string, so """ in "abc"" will return "True".\n' - '\n' - 'For user-defined classes which define the "__contains__()" ' - 'method, "x\n' - 'in y" returns "True" if "y.__contains__(x)" returns a true ' - 'value, and\n' - '"False" otherwise.\n' - '\n' - 'For user-defined classes which do not define "__contains__()" ' - 'but do\n' - 'define "__iter__()", "x in y" is "True" if some value "z" ' - 'with "x ==\n' - 'z" is produced while iterating over "y". If an exception is ' - 'raised\n' - 'during the iteration, it is as if "in" raised that ' - 'exception.\n' - '\n' - 'Lastly, the old-style iteration protocol is tried: if a class ' - 'defines\n' - '"__getitem__()", "x in y" is "True" if and only if there is a ' - 'non-\n' - 'negative integer index *i* such that "x == y[i]", and all ' - 'lower\n' - 'integer indices do not raise "IndexError" exception. (If any ' - 'other\n' - 'exception is raised, it is as if "in" raised that ' - 'exception).\n' - '\n' - 'The operator "not in" is defined to have the inverse true ' - 'value of\n' - '"in".\n' - '\n' - '\n' - 'Identity comparisons\n' - '====================\n' - '\n' - 'The operators "is" and "is not" test for object identity: "x ' - 'is y" is\n' - 'true if and only if *x* and *y* are the same object. Object ' - 'identity\n' - 'is determined using the "id()" function. "x is not y" yields ' - 'the\n' - 'inverse truth value. [4]\n', - 'compound': 'Compound statements\n' - '*******************\n' - '\n' - 'Compound statements contain (groups of) other statements; they ' - 'affect\n' - 'or control the execution of those other statements in some way. ' - 'In\n' - 'general, compound statements span multiple lines, although in ' - 'simple\n' - 'incarnations a whole compound statement may be contained in one ' - 'line.\n' - '\n' - 'The "if", "while" and "for" statements implement traditional ' - 'control\n' - 'flow constructs. "try" specifies exception handlers and/or ' - 'cleanup\n' - 'code for a group of statements, while the "with" statement ' - 'allows the\n' - 'execution of initialization and finalization code around a block ' - 'of\n' - 'code. Function and class definitions are also syntactically ' - 'compound\n' - 'statements.\n' - '\n' - 'A compound statement consists of one or more ‘clauses.’ A ' - 'clause\n' - 'consists of a header and a ‘suite.’ The clause headers of a\n' - 'particular compound statement are all at the same indentation ' - 'level.\n' - 'Each clause header begins with a uniquely identifying keyword ' - 'and ends\n' - 'with a colon. A suite is a group of statements controlled by a\n' - 'clause. A suite can be one or more semicolon-separated simple\n' - 'statements on the same line as the header, following the ' - 'header’s\n' - 'colon, or it can be one or more indented statements on ' - 'subsequent\n' - 'lines. Only the latter form of a suite can contain nested ' - 'compound\n' - 'statements; the following is illegal, mostly because it wouldn’t ' - 'be\n' - 'clear to which "if" clause a following "else" clause would ' - 'belong:\n' - '\n' - ' if test1: if test2: print(x)\n' - '\n' - 'Also note that the semicolon binds tighter than the colon in ' - 'this\n' - 'context, so that in the following example, either all or none of ' - 'the\n' - '"print()" calls are executed:\n' - '\n' - ' if x < y < z: print(x); print(y); print(z)\n' - '\n' - 'Summarizing:\n' - '\n' - ' compound_stmt ::= if_stmt\n' - ' | while_stmt\n' - ' | for_stmt\n' - ' | try_stmt\n' - ' | with_stmt\n' - ' | funcdef\n' - ' | classdef\n' - ' | async_with_stmt\n' - ' | async_for_stmt\n' - ' | async_funcdef\n' - ' suite ::= stmt_list NEWLINE | NEWLINE INDENT ' - 'statement+ DEDENT\n' - ' statement ::= stmt_list NEWLINE | compound_stmt\n' - ' stmt_list ::= simple_stmt (";" simple_stmt)* [";"]\n' - '\n' - 'Note that statements always end in a "NEWLINE" possibly followed ' - 'by a\n' - '"DEDENT". Also note that optional continuation clauses always ' - 'begin\n' - 'with a keyword that cannot start a statement, thus there are no\n' - 'ambiguities (the ‘dangling "else"’ problem is solved in Python ' - 'by\n' - 'requiring nested "if" statements to be indented).\n' - '\n' - 'The formatting of the grammar rules in the following sections ' - 'places\n' - 'each clause on a separate line for clarity.\n' - '\n' - '\n' - 'The "if" statement\n' - '==================\n' - '\n' - 'The "if" statement is used for conditional execution:\n' - '\n' - ' if_stmt ::= "if" expression ":" suite\n' - ' ("elif" expression ":" suite)*\n' - ' ["else" ":" suite]\n' - '\n' - 'It selects exactly one of the suites by evaluating the ' - 'expressions one\n' - 'by one until one is found to be true (see section Boolean ' - 'operations\n' - 'for the definition of true and false); then that suite is ' - 'executed\n' - '(and no other part of the "if" statement is executed or ' - 'evaluated).\n' - 'If all expressions are false, the suite of the "else" clause, ' - 'if\n' - 'present, is executed.\n' - '\n' - '\n' - 'The "while" statement\n' - '=====================\n' - '\n' - 'The "while" statement is used for repeated execution as long as ' - 'an\n' - 'expression is true:\n' - '\n' - ' while_stmt ::= "while" expression ":" suite\n' - ' ["else" ":" suite]\n' - '\n' - 'This repeatedly tests the expression and, if it is true, ' - 'executes the\n' - 'first suite; if the expression is false (which may be the first ' - 'time\n' - 'it is tested) the suite of the "else" clause, if present, is ' - 'executed\n' - 'and the loop terminates.\n' - '\n' - 'A "break" statement executed in the first suite terminates the ' - 'loop\n' - 'without executing the "else" clause’s suite. A "continue" ' - 'statement\n' - 'executed in the first suite skips the rest of the suite and goes ' - 'back\n' - 'to testing the expression.\n' - '\n' - '\n' - 'The "for" statement\n' - '===================\n' - '\n' - 'The "for" statement is used to iterate over the elements of a ' - 'sequence\n' - '(such as a string, tuple or list) or other iterable object:\n' - '\n' - ' for_stmt ::= "for" target_list "in" expression_list ":" ' - 'suite\n' - ' ["else" ":" suite]\n' - '\n' - 'The expression list is evaluated once; it should yield an ' - 'iterable\n' - 'object. An iterator is created for the result of the\n' - '"expression_list". The suite is then executed once for each ' - 'item\n' - 'provided by the iterator, in the order returned by the ' - 'iterator. Each\n' - 'item in turn is assigned to the target list using the standard ' - 'rules\n' - 'for assignments (see Assignment statements), and then the suite ' - 'is\n' - 'executed. When the items are exhausted (which is immediately ' - 'when the\n' - 'sequence is empty or an iterator raises a "StopIteration" ' - 'exception),\n' - 'the suite in the "else" clause, if present, is executed, and the ' - 'loop\n' - 'terminates.\n' - '\n' - 'A "break" statement executed in the first suite terminates the ' - 'loop\n' - 'without executing the "else" clause’s suite. A "continue" ' - 'statement\n' - 'executed in the first suite skips the rest of the suite and ' - 'continues\n' - 'with the next item, or with the "else" clause if there is no ' - 'next\n' - 'item.\n' - '\n' - 'The for-loop makes assignments to the variables(s) in the target ' - 'list.\n' - 'This overwrites all previous assignments to those variables ' - 'including\n' - 'those made in the suite of the for-loop:\n' - '\n' - ' for i in range(10):\n' - ' print(i)\n' - ' i = 5 # this will not affect the for-loop\n' - ' # because i will be overwritten with ' - 'the next\n' - ' # index in the range\n' - '\n' - 'Names in the target list are not deleted when the loop is ' - 'finished,\n' - 'but if the sequence is empty, they will not have been assigned ' - 'to at\n' - 'all by the loop. Hint: the built-in function "range()" returns ' - 'an\n' - 'iterator of integers suitable to emulate the effect of Pascal’s ' - '"for i\n' - ':= a to b do"; e.g., "list(range(3))" returns the list "[0, 1, ' - '2]".\n' - '\n' - 'Note: There is a subtlety when the sequence is being modified by ' - 'the\n' - ' loop (this can only occur for mutable sequences, e.g. lists). ' - 'An\n' - ' internal counter is used to keep track of which item is used ' - 'next,\n' - ' and this is incremented on each iteration. When this counter ' - 'has\n' - ' reached the length of the sequence the loop terminates. This ' - 'means\n' - ' that if the suite deletes the current (or a previous) item ' - 'from the\n' - ' sequence, the next item will be skipped (since it gets the ' - 'index of\n' - ' the current item which has already been treated). Likewise, ' - 'if the\n' - ' suite inserts an item in the sequence before the current item, ' - 'the\n' - ' current item will be treated again the next time through the ' - 'loop.\n' - ' This can lead to nasty bugs that can be avoided by making a\n' - ' temporary copy using a slice of the whole sequence, e.g.,\n' - '\n' - ' for x in a[:]:\n' - ' if x < 0: a.remove(x)\n' - '\n' - '\n' - 'The "try" statement\n' - '===================\n' - '\n' - 'The "try" statement specifies exception handlers and/or cleanup ' - 'code\n' - 'for a group of statements:\n' - '\n' - ' try_stmt ::= try1_stmt | try2_stmt\n' - ' try1_stmt ::= "try" ":" suite\n' - ' ("except" [expression ["as" identifier]] ":" ' - 'suite)+\n' - ' ["else" ":" suite]\n' - ' ["finally" ":" suite]\n' - ' try2_stmt ::= "try" ":" suite\n' - ' "finally" ":" suite\n' - '\n' - 'The "except" clause(s) specify one or more exception handlers. ' - 'When no\n' - 'exception occurs in the "try" clause, no exception handler is\n' - 'executed. When an exception occurs in the "try" suite, a search ' - 'for an\n' - 'exception handler is started. This search inspects the except ' - 'clauses\n' - 'in turn until one is found that matches the exception. An ' - 'expression-\n' - 'less except clause, if present, must be last; it matches any\n' - 'exception. For an except clause with an expression, that ' - 'expression\n' - 'is evaluated, and the clause matches the exception if the ' - 'resulting\n' - 'object is “compatible” with the exception. An object is ' - 'compatible\n' - 'with an exception if it is the class or a base class of the ' - 'exception\n' - 'object or a tuple containing an item compatible with the ' - 'exception.\n' - '\n' - 'If no except clause matches the exception, the search for an ' - 'exception\n' - 'handler continues in the surrounding code and on the invocation ' - 'stack.\n' - '[1]\n' - '\n' - 'If the evaluation of an expression in the header of an except ' - 'clause\n' - 'raises an exception, the original search for a handler is ' - 'canceled and\n' - 'a search starts for the new exception in the surrounding code ' - 'and on\n' - 'the call stack (it is treated as if the entire "try" statement ' - 'raised\n' - 'the exception).\n' - '\n' - 'When a matching except clause is found, the exception is ' - 'assigned to\n' - 'the target specified after the "as" keyword in that except ' - 'clause, if\n' - 'present, and the except clause’s suite is executed. All except\n' - 'clauses must have an executable block. When the end of this ' - 'block is\n' - 'reached, execution continues normally after the entire try ' - 'statement.\n' - '(This means that if two nested handlers exist for the same ' - 'exception,\n' - 'and the exception occurs in the try clause of the inner handler, ' - 'the\n' - 'outer handler will not handle the exception.)\n' - '\n' - 'When an exception has been assigned using "as target", it is ' - 'cleared\n' - 'at the end of the except clause. This is as if\n' - '\n' - ' except E as N:\n' - ' foo\n' - '\n' - 'was translated to\n' - '\n' - ' except E as N:\n' - ' try:\n' - ' foo\n' - ' finally:\n' - ' del N\n' - '\n' - 'This means the exception must be assigned to a different name to ' - 'be\n' - 'able to refer to it after the except clause. Exceptions are ' - 'cleared\n' - 'because with the traceback attached to them, they form a ' - 'reference\n' - 'cycle with the stack frame, keeping all locals in that frame ' - 'alive\n' - 'until the next garbage collection occurs.\n' - '\n' - 'Before an except clause’s suite is executed, details about the\n' - 'exception are stored in the "sys" module and can be accessed ' - 'via\n' - '"sys.exc_info()". "sys.exc_info()" returns a 3-tuple consisting ' - 'of the\n' - 'exception class, the exception instance and a traceback object ' - '(see\n' - 'section The standard type hierarchy) identifying the point in ' - 'the\n' - 'program where the exception occurred. "sys.exc_info()" values ' - 'are\n' - 'restored to their previous values (before the call) when ' - 'returning\n' - 'from a function that handled an exception.\n' - '\n' - 'The optional "else" clause is executed if the control flow ' - 'leaves the\n' - '"try" suite, no exception was raised, and no "return", ' - '"continue", or\n' - '"break" statement was executed. Exceptions in the "else" clause ' - 'are\n' - 'not handled by the preceding "except" clauses.\n' - '\n' - 'If "finally" is present, it specifies a ‘cleanup’ handler. The ' - '"try"\n' - 'clause is executed, including any "except" and "else" clauses. ' - 'If an\n' - 'exception occurs in any of the clauses and is not handled, the\n' - 'exception is temporarily saved. The "finally" clause is ' - 'executed. If\n' - 'there is a saved exception it is re-raised at the end of the ' - '"finally"\n' - 'clause. If the "finally" clause raises another exception, the ' - 'saved\n' - 'exception is set as the context of the new exception. If the ' - '"finally"\n' - 'clause executes a "return" or "break" statement, the saved ' - 'exception\n' - 'is discarded:\n' - '\n' - ' >>> def f():\n' - ' ... try:\n' - ' ... 1/0\n' - ' ... finally:\n' - ' ... return 42\n' - ' ...\n' - ' >>> f()\n' - ' 42\n' - '\n' - 'The exception information is not available to the program ' - 'during\n' - 'execution of the "finally" clause.\n' - '\n' - 'When a "return", "break" or "continue" statement is executed in ' - 'the\n' - '"try" suite of a "try"…"finally" statement, the "finally" clause ' - 'is\n' - 'also executed ‘on the way out.’ A "continue" statement is ' - 'illegal in\n' - 'the "finally" clause. (The reason is a problem with the current\n' - 'implementation — this restriction may be lifted in the future).\n' - '\n' - 'The return value of a function is determined by the last ' - '"return"\n' - 'statement executed. Since the "finally" clause always executes, ' - 'a\n' - '"return" statement executed in the "finally" clause will always ' - 'be the\n' - 'last one executed:\n' - '\n' - ' >>> def foo():\n' - ' ... try:\n' - " ... return 'try'\n" - ' ... finally:\n' - " ... return 'finally'\n" - ' ...\n' - ' >>> foo()\n' - " 'finally'\n" - '\n' - 'Additional information on exceptions can be found in section\n' - 'Exceptions, and information on using the "raise" statement to ' - 'generate\n' - 'exceptions may be found in section The raise statement.\n' - '\n' - '\n' - 'The "with" statement\n' - '====================\n' - '\n' - 'The "with" statement is used to wrap the execution of a block ' - 'with\n' - 'methods defined by a context manager (see section With ' - 'Statement\n' - 'Context Managers). This allows common "try"…"except"…"finally" ' - 'usage\n' - 'patterns to be encapsulated for convenient reuse.\n' - '\n' - ' with_stmt ::= "with" with_item ("," with_item)* ":" suite\n' - ' with_item ::= expression ["as" target]\n' - '\n' - 'The execution of the "with" statement with one “item” proceeds ' - 'as\n' - 'follows:\n' - '\n' - '1. The context expression (the expression given in the ' - '"with_item")\n' - ' is evaluated to obtain a context manager.\n' - '\n' - '2. The context manager’s "__exit__()" is loaded for later use.\n' - '\n' - '3. The context manager’s "__enter__()" method is invoked.\n' - '\n' - '4. If a target was included in the "with" statement, the return\n' - ' value from "__enter__()" is assigned to it.\n' - '\n' - ' Note: The "with" statement guarantees that if the ' - '"__enter__()"\n' - ' method returns without an error, then "__exit__()" will ' - 'always be\n' - ' called. Thus, if an error occurs during the assignment to ' - 'the\n' - ' target list, it will be treated the same as an error ' - 'occurring\n' - ' within the suite would be. See step 6 below.\n' - '\n' - '5. The suite is executed.\n' - '\n' - '6. The context manager’s "__exit__()" method is invoked. If an\n' - ' exception caused the suite to be exited, its type, value, ' - 'and\n' - ' traceback are passed as arguments to "__exit__()". Otherwise, ' - 'three\n' - ' "None" arguments are supplied.\n' - '\n' - ' If the suite was exited due to an exception, and the return ' - 'value\n' - ' from the "__exit__()" method was false, the exception is ' - 'reraised.\n' - ' If the return value was true, the exception is suppressed, ' - 'and\n' - ' execution continues with the statement following the "with"\n' - ' statement.\n' - '\n' - ' If the suite was exited for any reason other than an ' - 'exception, the\n' - ' return value from "__exit__()" is ignored, and execution ' - 'proceeds\n' - ' at the normal location for the kind of exit that was taken.\n' - '\n' - 'With more than one item, the context managers are processed as ' - 'if\n' - 'multiple "with" statements were nested:\n' - '\n' - ' with A() as a, B() as b:\n' - ' suite\n' - '\n' - 'is equivalent to\n' - '\n' - ' with A() as a:\n' - ' with B() as b:\n' - ' suite\n' - '\n' - 'Changed in version 3.1: Support for multiple context ' - 'expressions.\n' - '\n' - 'See also:\n' - '\n' - ' **PEP 343** - The “with” statement\n' - ' The specification, background, and examples for the Python ' - '"with"\n' - ' statement.\n' - '\n' - '\n' - 'Function definitions\n' - '====================\n' - '\n' - 'A function definition defines a user-defined function object ' - '(see\n' - 'section The standard type hierarchy):\n' - '\n' - ' funcdef ::= [decorators] "def" funcname "(" ' - '[parameter_list] ")"\n' - ' ["->" expression] ":" suite\n' - ' decorators ::= decorator+\n' - ' decorator ::= "@" dotted_name ["(" ' - '[argument_list [","]] ")"] NEWLINE\n' - ' dotted_name ::= identifier ("." identifier)*\n' - ' parameter_list ::= defparameter ("," defparameter)* ' - '["," [parameter_list_starargs]]\n' - ' | parameter_list_starargs\n' - ' parameter_list_starargs ::= "*" [parameter] ("," ' - 'defparameter)* ["," ["**" parameter [","]]]\n' - ' | "**" parameter [","]\n' - ' parameter ::= identifier [":" expression]\n' - ' defparameter ::= parameter ["=" expression]\n' - ' funcname ::= identifier\n' - '\n' - 'A function definition is an executable statement. Its execution ' - 'binds\n' - 'the function name in the current local namespace to a function ' - 'object\n' - '(a wrapper around the executable code for the function). This\n' - 'function object contains a reference to the current global ' - 'namespace\n' - 'as the global namespace to be used when the function is called.\n' - '\n' - 'The function definition does not execute the function body; this ' - 'gets\n' - 'executed only when the function is called. [2]\n' - '\n' - 'A function definition may be wrapped by one or more *decorator*\n' - 'expressions. Decorator expressions are evaluated when the ' - 'function is\n' - 'defined, in the scope that contains the function definition. ' - 'The\n' - 'result must be a callable, which is invoked with the function ' - 'object\n' - 'as the only argument. The returned value is bound to the ' - 'function name\n' - 'instead of the function object. Multiple decorators are applied ' - 'in\n' - 'nested fashion. For example, the following code\n' - '\n' - ' @f1(arg)\n' - ' @f2\n' - ' def func(): pass\n' - '\n' - 'is roughly equivalent to\n' - '\n' - ' def func(): pass\n' - ' func = f1(arg)(f2(func))\n' - '\n' - 'except that the original function is not temporarily bound to ' - 'the name\n' - '"func".\n' - '\n' - 'When one or more *parameters* have the form *parameter* "="\n' - '*expression*, the function is said to have “default parameter ' - 'values.”\n' - 'For a parameter with a default value, the corresponding ' - '*argument* may\n' - 'be omitted from a call, in which case the parameter’s default ' - 'value is\n' - 'substituted. If a parameter has a default value, all following\n' - 'parameters up until the “"*"” must also have a default value — ' - 'this is\n' - 'a syntactic restriction that is not expressed by the grammar.\n' - '\n' - '**Default parameter values are evaluated from left to right when ' - 'the\n' - 'function definition is executed.** This means that the ' - 'expression is\n' - 'evaluated once, when the function is defined, and that the same ' - '“pre-\n' - 'computed” value is used for each call. This is especially ' - 'important\n' - 'to understand when a default parameter is a mutable object, such ' - 'as a\n' - 'list or a dictionary: if the function modifies the object (e.g. ' - 'by\n' - 'appending an item to a list), the default value is in effect ' - 'modified.\n' - 'This is generally not what was intended. A way around this is ' - 'to use\n' - '"None" as the default, and explicitly test for it in the body of ' - 'the\n' - 'function, e.g.:\n' - '\n' - ' def whats_on_the_telly(penguin=None):\n' - ' if penguin is None:\n' - ' penguin = []\n' - ' penguin.append("property of the zoo")\n' - ' return penguin\n' - '\n' - 'Function call semantics are described in more detail in section ' - 'Calls.\n' - 'A function call always assigns values to all parameters ' - 'mentioned in\n' - 'the parameter list, either from position arguments, from ' - 'keyword\n' - 'arguments, or from default values. If the form “"*identifier"” ' - 'is\n' - 'present, it is initialized to a tuple receiving any excess ' - 'positional\n' - 'parameters, defaulting to the empty tuple. If the form\n' - '“"**identifier"” is present, it is initialized to a new ordered\n' - 'mapping receiving any excess keyword arguments, defaulting to a ' - 'new\n' - 'empty mapping of the same type. Parameters after “"*"” or\n' - '“"*identifier"” are keyword-only parameters and may only be ' - 'passed\n' - 'used keyword arguments.\n' - '\n' - 'Parameters may have annotations of the form “": expression"” ' - 'following\n' - 'the parameter name. Any parameter may have an annotation even ' - 'those\n' - 'of the form "*identifier" or "**identifier". Functions may ' - 'have\n' - '“return” annotation of the form “"-> expression"” after the ' - 'parameter\n' - 'list. These annotations can be any valid Python expression and ' - 'are\n' - 'evaluated when the function definition is executed. Annotations ' - 'may\n' - 'be evaluated in a different order than they appear in the source ' - 'code.\n' - 'The presence of annotations does not change the semantics of a\n' - 'function. The annotation values are available as values of a\n' - 'dictionary keyed by the parameters’ names in the ' - '"__annotations__"\n' - 'attribute of the function object.\n' - '\n' - 'It is also possible to create anonymous functions (functions not ' - 'bound\n' - 'to a name), for immediate use in expressions. This uses lambda\n' - 'expressions, described in section Lambdas. Note that the ' - 'lambda\n' - 'expression is merely a shorthand for a simplified function ' - 'definition;\n' - 'a function defined in a “"def"” statement can be passed around ' - 'or\n' - 'assigned to another name just like a function defined by a ' - 'lambda\n' - 'expression. The “"def"” form is actually more powerful since ' - 'it\n' - 'allows the execution of multiple statements and annotations.\n' - '\n' - '**Programmer’s note:** Functions are first-class objects. A ' - '“"def"”\n' - 'statement executed inside a function definition defines a local\n' - 'function that can be returned or passed around. Free variables ' - 'used\n' - 'in the nested function can access the local variables of the ' - 'function\n' - 'containing the def. See section Naming and binding for ' - 'details.\n' - '\n' - 'See also:\n' - '\n' - ' **PEP 3107** - Function Annotations\n' - ' The original specification for function annotations.\n' - '\n' - '\n' - 'Class definitions\n' - '=================\n' - '\n' - 'A class definition defines a class object (see section The ' - 'standard\n' - 'type hierarchy):\n' - '\n' - ' classdef ::= [decorators] "class" classname [inheritance] ' - '":" suite\n' - ' inheritance ::= "(" [argument_list] ")"\n' - ' classname ::= identifier\n' - '\n' - 'A class definition is an executable statement. The inheritance ' - 'list\n' - 'usually gives a list of base classes (see Metaclasses for more\n' - 'advanced uses), so each item in the list should evaluate to a ' - 'class\n' - 'object which allows subclassing. Classes without an inheritance ' - 'list\n' - 'inherit, by default, from the base class "object"; hence,\n' - '\n' - ' class Foo:\n' - ' pass\n' - '\n' - 'is equivalent to\n' - '\n' - ' class Foo(object):\n' - ' pass\n' - '\n' - 'The class’s suite is then executed in a new execution frame ' - '(see\n' - 'Naming and binding), using a newly created local namespace and ' - 'the\n' - 'original global namespace. (Usually, the suite contains mostly\n' - 'function definitions.) When the class’s suite finishes ' - 'execution, its\n' - 'execution frame is discarded but its local namespace is saved. ' - '[3] A\n' - 'class object is then created using the inheritance list for the ' - 'base\n' - 'classes and the saved local namespace for the attribute ' - 'dictionary.\n' - 'The class name is bound to this class object in the original ' - 'local\n' - 'namespace.\n' - '\n' - 'The order in which attributes are defined in the class body is\n' - 'preserved in the new class’s "__dict__". Note that this is ' - 'reliable\n' - 'only right after the class is created and only for classes that ' - 'were\n' - 'defined using the definition syntax.\n' - '\n' - 'Class creation can be customized heavily using metaclasses.\n' - '\n' - 'Classes can also be decorated: just like when decorating ' - 'functions,\n' - '\n' - ' @f1(arg)\n' - ' @f2\n' - ' class Foo: pass\n' - '\n' - 'is roughly equivalent to\n' - '\n' - ' class Foo: pass\n' - ' Foo = f1(arg)(f2(Foo))\n' - '\n' - 'The evaluation rules for the decorator expressions are the same ' - 'as for\n' - 'function decorators. The result is then bound to the class ' - 'name.\n' - '\n' - '**Programmer’s note:** Variables defined in the class definition ' - 'are\n' - 'class attributes; they are shared by instances. Instance ' - 'attributes\n' - 'can be set in a method with "self.name = value". Both class ' - 'and\n' - 'instance attributes are accessible through the notation ' - '“"self.name"”,\n' - 'and an instance attribute hides a class attribute with the same ' - 'name\n' - 'when accessed in this way. Class attributes can be used as ' - 'defaults\n' - 'for instance attributes, but using mutable values there can lead ' - 'to\n' - 'unexpected results. Descriptors can be used to create instance\n' - 'variables with different implementation details.\n' - '\n' - 'See also:\n' - '\n' - ' **PEP 3115** - Metaclasses in Python 3000\n' - ' The proposal that changed the declaration of metaclasses to ' - 'the\n' - ' current syntax, and the semantics for how classes with\n' - ' metaclasses are constructed.\n' - '\n' - ' **PEP 3129** - Class Decorators\n' - ' The proposal that added class decorators. Function and ' - 'method\n' - ' decorators were introduced in **PEP 318**.\n' - '\n' - '\n' - 'Coroutines\n' - '==========\n' - '\n' - 'New in version 3.5.\n' - '\n' - '\n' - 'Coroutine function definition\n' - '-----------------------------\n' - '\n' - ' async_funcdef ::= [decorators] "async" "def" funcname "(" ' - '[parameter_list] ")"\n' - ' ["->" expression] ":" suite\n' - '\n' - 'Execution of Python coroutines can be suspended and resumed at ' - 'many\n' - 'points (see *coroutine*). In the body of a coroutine, any ' - '"await" and\n' - '"async" identifiers become reserved keywords; "await" ' - 'expressions,\n' - '"async for" and "async with" can only be used in coroutine ' - 'bodies.\n' - '\n' - 'Functions defined with "async def" syntax are always coroutine\n' - 'functions, even if they do not contain "await" or "async" ' - 'keywords.\n' - '\n' - 'It is a "SyntaxError" to use "yield from" expressions in "async ' - 'def"\n' - 'coroutines.\n' - '\n' - 'An example of a coroutine function:\n' - '\n' - ' async def func(param1, param2):\n' - ' do_stuff()\n' - ' await some_coroutine()\n' - '\n' - '\n' - 'The "async for" statement\n' - '-------------------------\n' - '\n' - ' async_for_stmt ::= "async" for_stmt\n' - '\n' - 'An *asynchronous iterable* is able to call asynchronous code in ' - 'its\n' - '*iter* implementation, and *asynchronous iterator* can call\n' - 'asynchronous code in its *next* method.\n' - '\n' - 'The "async for" statement allows convenient iteration over\n' - 'asynchronous iterators.\n' - '\n' - 'The following code:\n' - '\n' - ' async for TARGET in ITER:\n' - ' BLOCK\n' - ' else:\n' - ' BLOCK2\n' - '\n' - 'Is semantically equivalent to:\n' - '\n' - ' iter = (ITER)\n' - ' iter = type(iter).__aiter__(iter)\n' - ' running = True\n' - ' while running:\n' - ' try:\n' - ' TARGET = await type(iter).__anext__(iter)\n' - ' except StopAsyncIteration:\n' - ' running = False\n' - ' else:\n' - ' BLOCK\n' - ' else:\n' - ' BLOCK2\n' - '\n' - 'See also "__aiter__()" and "__anext__()" for details.\n' - '\n' - 'It is a "SyntaxError" to use "async for" statement outside of ' - 'an\n' - '"async def" function.\n' - '\n' - '\n' - 'The "async with" statement\n' - '--------------------------\n' - '\n' - ' async_with_stmt ::= "async" with_stmt\n' - '\n' - 'An *asynchronous context manager* is a *context manager* that is ' - 'able\n' - 'to suspend execution in its *enter* and *exit* methods.\n' - '\n' - 'The following code:\n' - '\n' - ' async with EXPR as VAR:\n' - ' BLOCK\n' - '\n' - 'Is semantically equivalent to:\n' - '\n' - ' mgr = (EXPR)\n' - ' aexit = type(mgr).__aexit__\n' - ' aenter = type(mgr).__aenter__(mgr)\n' - '\n' - ' VAR = await aenter\n' - ' try:\n' - ' BLOCK\n' - ' except:\n' - ' if not await aexit(mgr, *sys.exc_info()):\n' - ' raise\n' - ' else:\n' - ' await aexit(mgr, None, None, None)\n' - '\n' - 'See also "__aenter__()" and "__aexit__()" for details.\n' - '\n' - 'It is a "SyntaxError" to use "async with" statement outside of ' - 'an\n' - '"async def" function.\n' - '\n' - 'See also:\n' - '\n' - ' **PEP 492** - Coroutines with async and await syntax\n' - ' The proposal that made coroutines a proper standalone ' - 'concept in\n' - ' Python, and added supporting syntax.\n' - '\n' - '-[ Footnotes ]-\n' - '\n' - '[1] The exception is propagated to the invocation stack unless\n' - ' there is a "finally" clause which happens to raise another\n' - ' exception. That new exception causes the old one to be ' - 'lost.\n' - '\n' - '[2] A string literal appearing as the first statement in the\n' - ' function body is transformed into the function’s "__doc__"\n' - ' attribute and therefore the function’s *docstring*.\n' - '\n' - '[3] A string literal appearing as the first statement in the ' - 'class\n' - ' body is transformed into the namespace’s "__doc__" item and\n' - ' therefore the class’s *docstring*.\n', - 'context-managers': 'With Statement Context Managers\n' - '*******************************\n' - '\n' - 'A *context manager* is an object that defines the ' - 'runtime context to\n' - 'be established when executing a "with" statement. The ' - 'context manager\n' - 'handles the entry into, and the exit from, the desired ' - 'runtime context\n' - 'for the execution of the block of code. Context ' - 'managers are normally\n' - 'invoked using the "with" statement (described in section ' - 'The with\n' - 'statement), but can also be used by directly invoking ' - 'their methods.\n' - '\n' - 'Typical uses of context managers include saving and ' - 'restoring various\n' - 'kinds of global state, locking and unlocking resources, ' - 'closing opened\n' - 'files, etc.\n' - '\n' - 'For more information on context managers, see Context ' - 'Manager Types.\n' - '\n' - 'object.__enter__(self)\n' - '\n' - ' Enter the runtime context related to this object. The ' - '"with"\n' - ' statement will bind this method’s return value to the ' - 'target(s)\n' - ' specified in the "as" clause of the statement, if ' - 'any.\n' - '\n' - 'object.__exit__(self, exc_type, exc_value, traceback)\n' - '\n' - ' Exit the runtime context related to this object. The ' - 'parameters\n' - ' describe the exception that caused the context to be ' - 'exited. If the\n' - ' context was exited without an exception, all three ' - 'arguments will\n' - ' be "None".\n' + 'An augmented assignment statement like "x += 1" can be ' + 'rewritten as "x\n' + '= x + 1" to achieve a similar, but not exactly equal effect. In ' + 'the\n' + 'augmented version, "x" is only evaluated once. Also, when ' + 'possible,\n' + 'the actual operation is performed *in-place*, meaning that ' + 'rather than\n' + 'creating a new object and assigning that to the target, the old ' + 'object\n' + 'is modified instead.\n' + '\n' + 'Unlike normal assignments, augmented assignments evaluate the ' + 'left-\n' + 'hand side *before* evaluating the right-hand side. For ' + 'example, "a[i]\n' + '+= f(x)" first looks-up "a[i]", then it evaluates "f(x)" and ' + 'performs\n' + 'the addition, and lastly, it writes the result back to "a[i]".\n' + '\n' + 'With the exception of assigning to tuples and multiple targets ' + 'in a\n' + 'single statement, the assignment done by augmented assignment\n' + 'statements is handled the same way as normal assignments. ' + 'Similarly,\n' + 'with the exception of the possible *in-place* behavior, the ' + 'binary\n' + 'operation performed by augmented assignment is the same as the ' + 'normal\n' + 'binary operations.\n' + '\n' + 'For targets which are attribute references, the same caveat ' + 'about\n' + 'class and instance attributes applies as for regular ' + 'assignments.\n', + 'await': 'Await expression\n' + '****************\n' + '\n' + 'Suspend the execution of *coroutine* on an *awaitable* object. Can\n' + 'only be used inside a *coroutine function*.\n' + '\n' + ' await_expr ::= "await" primary\n' + '\n' + 'Added in version 3.5.\n', + 'binary': 'Binary arithmetic operations\n' + '****************************\n' + '\n' + 'The binary arithmetic operations have the conventional priority\n' + 'levels. Note that some of these operations also apply to certain ' + 'non-\n' + 'numeric types. Apart from the power operator, there are only two\n' + 'levels, one for multiplicative operators and one for additive\n' + 'operators:\n' + '\n' + ' m_expr ::= u_expr | m_expr "*" u_expr | m_expr "@" m_expr |\n' + ' m_expr "//" u_expr | m_expr "/" u_expr |\n' + ' m_expr "%" u_expr\n' + ' a_expr ::= m_expr | a_expr "+" m_expr | a_expr "-" m_expr\n' + '\n' + 'The "*" (multiplication) operator yields the product of its ' + 'arguments.\n' + 'The arguments must either both be numbers, or one argument must be ' + 'an\n' + 'integer and the other must be a sequence. In the former case, the\n' + 'numbers are converted to a common type and then multiplied ' + 'together.\n' + 'In the latter case, sequence repetition is performed; a negative\n' + 'repetition factor yields an empty sequence.\n' + '\n' + 'This operation can be customized using the special "__mul__()" ' + 'and\n' + '"__rmul__()" methods.\n' + '\n' + 'The "@" (at) operator is intended to be used for matrix\n' + 'multiplication. No builtin Python types implement this operator.\n' + '\n' + 'This operation can be customized using the special "__matmul__()" ' + 'and\n' + '"__rmatmul__()" methods.\n' + '\n' + 'Added in version 3.5.\n' + '\n' + 'The "/" (division) and "//" (floor division) operators yield the\n' + 'quotient of their arguments. The numeric arguments are first\n' + 'converted to a common type. Division of integers yields a float, ' + 'while\n' + 'floor division of integers results in an integer; the result is ' + 'that\n' + 'of mathematical division with the ‘floor’ function applied to the\n' + 'result. Division by zero raises the "ZeroDivisionError" ' + 'exception.\n' + '\n' + 'The division operation can be customized using the special\n' + '"__truediv__()" and "__rtruediv__()" methods. The floor division\n' + 'operation can be customized using the special "__floordiv__()" ' + 'and\n' + '"__rfloordiv__()" methods.\n' + '\n' + 'The "%" (modulo) operator yields the remainder from the division ' + 'of\n' + 'the first argument by the second. The numeric arguments are ' + 'first\n' + 'converted to a common type. A zero right argument raises the\n' + '"ZeroDivisionError" exception. The arguments may be ' + 'floating-point\n' + 'numbers, e.g., "3.14%0.7" equals "0.34" (since "3.14" equals ' + '"4*0.7 +\n' + '0.34".) The modulo operator always yields a result with the same ' + 'sign\n' + 'as its second operand (or zero); the absolute value of the result ' + 'is\n' + 'strictly smaller than the absolute value of the second operand ' + '[1].\n' + '\n' + 'The floor division and modulo operators are connected by the ' + 'following\n' + 'identity: "x == (x//y)*y + (x%y)". Floor division and modulo are ' + 'also\n' + 'connected with the built-in function "divmod()": "divmod(x, y) ==\n' + '(x//y, x%y)". [2].\n' + '\n' + 'In addition to performing the modulo operation on numbers, the ' + '"%"\n' + 'operator is also overloaded by string objects to perform ' + 'old-style\n' + 'string formatting (also known as interpolation). The syntax for\n' + 'string formatting is described in the Python Library Reference,\n' + 'section printf-style String Formatting.\n' + '\n' + 'The *modulo* operation can be customized using the special ' + '"__mod__()"\n' + 'and "__rmod__()" methods.\n' + '\n' + 'The floor division operator, the modulo operator, and the ' + '"divmod()"\n' + 'function are not defined for complex numbers. Instead, convert to ' + 'a\n' + 'floating-point number using the "abs()" function if appropriate.\n' + '\n' + 'The "+" (addition) operator yields the sum of its arguments. The\n' + 'arguments must either both be numbers or both be sequences of the ' + 'same\n' + 'type. In the former case, the numbers are converted to a common ' + 'type\n' + 'and then added together. In the latter case, the sequences are\n' + 'concatenated.\n' + '\n' + 'This operation can be customized using the special "__add__()" ' + 'and\n' + '"__radd__()" methods.\n' + '\n' + 'The "-" (subtraction) operator yields the difference of its ' + 'arguments.\n' + 'The numeric arguments are first converted to a common type.\n' + '\n' + 'This operation can be customized using the special "__sub__()" ' + 'and\n' + '"__rsub__()" methods.\n', + 'bitwise': 'Binary bitwise operations\n' + '*************************\n' '\n' - ' If an exception is supplied, and the method wishes to ' - 'suppress the\n' - ' exception (i.e., prevent it from being propagated), ' - 'it should\n' - ' return a true value. Otherwise, the exception will be ' - 'processed\n' - ' normally upon exit from this method.\n' + 'Each of the three bitwise operations has a different priority ' + 'level:\n' '\n' - ' Note that "__exit__()" methods should not reraise the ' - 'passed-in\n' - ' exception; this is the caller’s responsibility.\n' + ' and_expr ::= shift_expr | and_expr "&" shift_expr\n' + ' xor_expr ::= and_expr | xor_expr "^" and_expr\n' + ' or_expr ::= xor_expr | or_expr "|" xor_expr\n' '\n' - 'See also:\n' + 'The "&" operator yields the bitwise AND of its arguments, which ' + 'must\n' + 'be integers or one of them must be a custom object overriding\n' + '"__and__()" or "__rand__()" special methods.\n' '\n' - ' **PEP 343** - The “with” statement\n' - ' The specification, background, and examples for the ' - 'Python "with"\n' - ' statement.\n', - 'continue': 'The "continue" statement\n' - '************************\n' - '\n' - ' continue_stmt ::= "continue"\n' - '\n' - '"continue" may only occur syntactically nested in a "for" or ' - '"while"\n' - 'loop, but not nested in a function or class definition or ' - '"finally"\n' - 'clause within that loop. It continues with the next cycle of ' - 'the\n' - 'nearest enclosing loop.\n' - '\n' - 'When "continue" passes control out of a "try" statement with a\n' - '"finally" clause, that "finally" clause is executed before ' - 'really\n' - 'starting the next loop cycle.\n', - 'conversions': 'Arithmetic conversions\n' - '**********************\n' - '\n' - 'When a description of an arithmetic operator below uses the ' - 'phrase\n' - '“the numeric arguments are converted to a common type,” this ' - 'means\n' - 'that the operator implementation for built-in types works as ' - 'follows:\n' - '\n' - '* If either argument is a complex number, the other is ' - 'converted to\n' - ' complex;\n' - '\n' - '* otherwise, if either argument is a floating point number, ' - 'the\n' - ' other is converted to floating point;\n' - '\n' - '* otherwise, both must be integers and no conversion is ' - 'necessary.\n' - '\n' - 'Some additional rules apply for certain operators (e.g., a ' - 'string as a\n' - 'left argument to the ‘%’ operator). Extensions must define ' - 'their own\n' - 'conversion behavior.\n', - 'customization': 'Basic customization\n' - '*******************\n' - '\n' - 'object.__new__(cls[, ...])\n' - '\n' - ' Called to create a new instance of class *cls*. ' - '"__new__()" is a\n' - ' static method (special-cased so you need not declare it ' - 'as such)\n' - ' that takes the class of which an instance was requested ' - 'as its\n' - ' first argument. The remaining arguments are those ' - 'passed to the\n' - ' object constructor expression (the call to the class). ' - 'The return\n' - ' value of "__new__()" should be the new object instance ' - '(usually an\n' - ' instance of *cls*).\n' - '\n' - ' Typical implementations create a new instance of the ' - 'class by\n' - ' invoking the superclass’s "__new__()" method using\n' - ' "super().__new__(cls[, ...])" with appropriate arguments ' - 'and then\n' - ' modifying the newly-created instance as necessary before ' - 'returning\n' - ' it.\n' - '\n' - ' If "__new__()" returns an instance of *cls*, then the ' - 'new\n' - ' instance’s "__init__()" method will be invoked like\n' - ' "__init__(self[, ...])", where *self* is the new ' - 'instance and the\n' - ' remaining arguments are the same as were passed to ' - '"__new__()".\n' - '\n' - ' If "__new__()" does not return an instance of *cls*, ' - 'then the new\n' - ' instance’s "__init__()" method will not be invoked.\n' - '\n' - ' "__new__()" is intended mainly to allow subclasses of ' - 'immutable\n' - ' types (like int, str, or tuple) to customize instance ' - 'creation. It\n' - ' is also commonly overridden in custom metaclasses in ' - 'order to\n' - ' customize class creation.\n' - '\n' - 'object.__init__(self[, ...])\n' - '\n' - ' Called after the instance has been created (by ' - '"__new__()"), but\n' - ' before it is returned to the caller. The arguments are ' - 'those\n' - ' passed to the class constructor expression. If a base ' - 'class has an\n' - ' "__init__()" method, the derived class’s "__init__()" ' - 'method, if\n' - ' any, must explicitly call it to ensure proper ' - 'initialization of the\n' - ' base class part of the instance; for example:\n' - ' "super().__init__([args...])".\n' - '\n' - ' Because "__new__()" and "__init__()" work together in ' - 'constructing\n' - ' objects ("__new__()" to create it, and "__init__()" to ' - 'customize\n' - ' it), no non-"None" value may be returned by ' - '"__init__()"; doing so\n' - ' will cause a "TypeError" to be raised at runtime.\n' - '\n' - 'object.__del__(self)\n' - '\n' - ' Called when the instance is about to be destroyed. This ' - 'is also\n' - ' called a finalizer or (improperly) a destructor. If a ' - 'base class\n' - ' has a "__del__()" method, the derived class’s ' - '"__del__()" method,\n' - ' if any, must explicitly call it to ensure proper ' - 'deletion of the\n' - ' base class part of the instance.\n' - '\n' - ' It is possible (though not recommended!) for the ' - '"__del__()" method\n' - ' to postpone destruction of the instance by creating a ' - 'new reference\n' - ' to it. This is called object *resurrection*. It is\n' - ' implementation-dependent whether "__del__()" is called a ' - 'second\n' - ' time when a resurrected object is about to be destroyed; ' - 'the\n' - ' current *CPython* implementation only calls it once.\n' - '\n' - ' It is not guaranteed that "__del__()" methods are called ' - 'for\n' - ' objects that still exist when the interpreter exits.\n' - '\n' - ' Note: "del x" doesn’t directly call "x.__del__()" — the ' - 'former\n' - ' decrements the reference count for "x" by one, and the ' - 'latter is\n' - ' only called when "x"’s reference count reaches zero.\n' - '\n' - ' **CPython implementation detail:** It is possible for a ' - 'reference\n' - ' cycle to prevent the reference count of an object from ' - 'going to\n' - ' zero. In this case, the cycle will be later detected ' - 'and deleted\n' - ' by the *cyclic garbage collector*. A common cause of ' - 'reference\n' - ' cycles is when an exception has been caught in a local ' - 'variable.\n' - ' The frame’s locals then reference the exception, which ' - 'references\n' - ' its own traceback, which references the locals of all ' - 'frames caught\n' - ' in the traceback.\n' - '\n' - ' See also: Documentation for the "gc" module.\n' - '\n' - ' Warning: Due to the precarious circumstances under ' - 'which\n' - ' "__del__()" methods are invoked, exceptions that occur ' - 'during\n' - ' their execution are ignored, and a warning is printed ' - 'to\n' - ' "sys.stderr" instead. In particular:\n' - '\n' - ' * "__del__()" can be invoked when arbitrary code is ' - 'being\n' - ' executed, including from any arbitrary thread. If ' - '"__del__()"\n' - ' needs to take a lock or invoke any other blocking ' - 'resource, it\n' - ' may deadlock as the resource may already be taken by ' - 'the code\n' - ' that gets interrupted to execute "__del__()".\n' - '\n' - ' * "__del__()" can be executed during interpreter ' - 'shutdown. As\n' - ' a consequence, the global variables it needs to ' - 'access\n' - ' (including other modules) may already have been ' - 'deleted or set\n' - ' to "None". Python guarantees that globals whose name ' - 'begins\n' - ' with a single underscore are deleted from their ' - 'module before\n' - ' other globals are deleted; if no other references to ' - 'such\n' - ' globals exist, this may help in assuring that ' - 'imported modules\n' - ' are still available at the time when the "__del__()" ' - 'method is\n' - ' called.\n' - '\n' - 'object.__repr__(self)\n' - '\n' - ' Called by the "repr()" built-in function to compute the ' - '“official”\n' - ' string representation of an object. If at all possible, ' - 'this\n' - ' should look like a valid Python expression that could be ' - 'used to\n' - ' recreate an object with the same value (given an ' - 'appropriate\n' - ' environment). If this is not possible, a string of the ' - 'form\n' - ' "<...some useful description...>" should be returned. ' - 'The return\n' - ' value must be a string object. If a class defines ' - '"__repr__()" but\n' - ' not "__str__()", then "__repr__()" is also used when an ' - '“informal”\n' - ' string representation of instances of that class is ' - 'required.\n' - '\n' - ' This is typically used for debugging, so it is important ' - 'that the\n' - ' representation is information-rich and unambiguous.\n' - '\n' - 'object.__str__(self)\n' - '\n' - ' Called by "str(object)" and the built-in functions ' - '"format()" and\n' - ' "print()" to compute the “informal” or nicely printable ' - 'string\n' - ' representation of an object. The return value must be a ' - 'string\n' - ' object.\n' - '\n' - ' This method differs from "object.__repr__()" in that ' - 'there is no\n' - ' expectation that "__str__()" return a valid Python ' - 'expression: a\n' - ' more convenient or concise representation can be used.\n' - '\n' - ' The default implementation defined by the built-in type ' - '"object"\n' - ' calls "object.__repr__()".\n' - '\n' - 'object.__bytes__(self)\n' - '\n' - ' Called by bytes to compute a byte-string representation ' - 'of an\n' - ' object. This should return a "bytes" object.\n' - '\n' - 'object.__format__(self, format_spec)\n' - '\n' - ' Called by the "format()" built-in function, and by ' - 'extension,\n' - ' evaluation of formatted string literals and the ' - '"str.format()"\n' - ' method, to produce a “formatted” string representation ' - 'of an\n' - ' object. The "format_spec" argument is a string that ' - 'contains a\n' - ' description of the formatting options desired. The ' - 'interpretation\n' - ' of the "format_spec" argument is up to the type ' - 'implementing\n' - ' "__format__()", however most classes will either ' - 'delegate\n' - ' formatting to one of the built-in types, or use a ' - 'similar\n' - ' formatting option syntax.\n' - '\n' - ' See Format Specification Mini-Language for a description ' - 'of the\n' - ' standard formatting syntax.\n' - '\n' - ' The return value must be a string object.\n' - '\n' - ' Changed in version 3.4: The __format__ method of ' - '"object" itself\n' - ' raises a "TypeError" if passed any non-empty string.\n' - '\n' - 'object.__lt__(self, other)\n' - 'object.__le__(self, other)\n' - 'object.__eq__(self, other)\n' - 'object.__ne__(self, other)\n' - 'object.__gt__(self, other)\n' - 'object.__ge__(self, other)\n' - '\n' - ' These are the so-called “rich comparison” methods. The\n' - ' correspondence between operator symbols and method names ' - 'is as\n' - ' follows: "xy" calls\n' - ' "x.__gt__(y)", and "x>=y" calls "x.__ge__(y)".\n' - '\n' - ' A rich comparison method may return the singleton ' - '"NotImplemented"\n' - ' if it does not implement the operation for a given pair ' - 'of\n' - ' arguments. By convention, "False" and "True" are ' - 'returned for a\n' - ' successful comparison. However, these methods can return ' - 'any value,\n' - ' so if the comparison operator is used in a Boolean ' - 'context (e.g.,\n' - ' in the condition of an "if" statement), Python will call ' - '"bool()"\n' - ' on the value to determine if the result is true or ' - 'false.\n' - '\n' - ' By default, "__ne__()" delegates to "__eq__()" and ' - 'inverts the\n' - ' result unless it is "NotImplemented". There are no ' - 'other implied\n' - ' relationships among the comparison operators, for ' - 'example, the\n' - ' truth of "(x.__hash__".\n' - '\n' - ' If a class that does not override "__eq__()" wishes to ' - 'suppress\n' - ' hash support, it should include "__hash__ = None" in the ' - 'class\n' - ' definition. A class which defines its own "__hash__()" ' - 'that\n' - ' explicitly raises a "TypeError" would be incorrectly ' - 'identified as\n' - ' hashable by an "isinstance(obj, collections.Hashable)" ' - 'call.\n' - '\n' - ' Note: By default, the "__hash__()" values of str, bytes ' - 'and\n' - ' datetime objects are “salted” with an unpredictable ' - 'random value.\n' - ' Although they remain constant within an individual ' - 'Python\n' - ' process, they are not predictable between repeated ' - 'invocations of\n' - ' Python.This is intended to provide protection against ' - 'a denial-\n' - ' of-service caused by carefully-chosen inputs that ' - 'exploit the\n' - ' worst case performance of a dict insertion, O(n^2) ' - 'complexity.\n' - ' See ' - 'http://www.ocert.org/advisories/ocert-2011-003.html for\n' - ' details.Changing hash values affects the iteration ' - 'order of\n' - ' dicts, sets and other mappings. Python has never made ' - 'guarantees\n' - ' about this ordering (and it typically varies between ' - '32-bit and\n' - ' 64-bit builds).See also "PYTHONHASHSEED".\n' - '\n' - ' Changed in version 3.3: Hash randomization is enabled by ' - 'default.\n' - '\n' - 'object.__bool__(self)\n' - '\n' - ' Called to implement truth value testing and the built-in ' - 'operation\n' - ' "bool()"; should return "False" or "True". When this ' - 'method is not\n' - ' defined, "__len__()" is called, if it is defined, and ' - 'the object is\n' - ' considered true if its result is nonzero. If a class ' - 'defines\n' - ' neither "__len__()" nor "__bool__()", all its instances ' - 'are\n' - ' considered true.\n', - 'debugger': '"pdb" — The Python Debugger\n' - '***************************\n' - '\n' - '**Source code:** Lib/pdb.py\n' - '\n' - '======================================================================\n' - '\n' - 'The module "pdb" defines an interactive source code debugger ' - 'for\n' - 'Python programs. It supports setting (conditional) breakpoints ' - 'and\n' - 'single stepping at the source line level, inspection of stack ' - 'frames,\n' - 'source code listing, and evaluation of arbitrary Python code in ' - 'the\n' - 'context of any stack frame. It also supports post-mortem ' - 'debugging\n' - 'and can be called under program control.\n' - '\n' - 'The debugger is extensible – it is actually defined as the ' - 'class\n' - '"Pdb". This is currently undocumented but easily understood by ' - 'reading\n' - 'the source. The extension interface uses the modules "bdb" and ' - '"cmd".\n' - '\n' - 'The debugger’s prompt is "(Pdb)". Typical usage to run a program ' - 'under\n' - 'control of the debugger is:\n' - '\n' - ' >>> import pdb\n' - ' >>> import mymodule\n' - " >>> pdb.run('mymodule.test()')\n" - ' > (0)?()\n' - ' (Pdb) continue\n' - ' > (1)?()\n' - ' (Pdb) continue\n' - " NameError: 'spam'\n" - ' > (1)?()\n' - ' (Pdb)\n' - '\n' - 'Changed in version 3.3: Tab-completion via the "readline" module ' - 'is\n' - 'available for commands and command arguments, e.g. the current ' - 'global\n' - 'and local names are offered as arguments of the "p" command.\n' - '\n' - '"pdb.py" can also be invoked as a script to debug other ' - 'scripts. For\n' - 'example:\n' - '\n' - ' python3 -m pdb myscript.py\n' - '\n' - 'When invoked as a script, pdb will automatically enter ' - 'post-mortem\n' - 'debugging if the program being debugged exits abnormally. After ' - 'post-\n' - 'mortem debugging (or after normal exit of the program), pdb ' - 'will\n' - 'restart the program. Automatic restarting preserves pdb’s state ' - '(such\n' - 'as breakpoints) and in most cases is more useful than quitting ' - 'the\n' - 'debugger upon program’s exit.\n' - '\n' - 'New in version 3.2: "pdb.py" now accepts a "-c" option that ' - 'executes\n' - 'commands as if given in a ".pdbrc" file, see Debugger Commands.\n' - '\n' - 'The typical usage to break into the debugger from a running ' - 'program is\n' - 'to insert\n' - '\n' - ' import pdb; pdb.set_trace()\n' - '\n' - 'at the location you want to break into the debugger. You can ' - 'then\n' - 'step through the code following this statement, and continue ' - 'running\n' - 'without the debugger using the "continue" command.\n' - '\n' - 'The typical usage to inspect a crashed program is:\n' - '\n' - ' >>> import pdb\n' - ' >>> import mymodule\n' - ' >>> mymodule.test()\n' - ' Traceback (most recent call last):\n' - ' File "", line 1, in \n' - ' File "./mymodule.py", line 4, in test\n' - ' test2()\n' - ' File "./mymodule.py", line 3, in test2\n' - ' print(spam)\n' - ' NameError: spam\n' - ' >>> pdb.pm()\n' - ' > ./mymodule.py(3)test2()\n' - ' -> print(spam)\n' - ' (Pdb)\n' - '\n' - 'The module defines the following functions; each enters the ' - 'debugger\n' - 'in a slightly different way:\n' - '\n' - 'pdb.run(statement, globals=None, locals=None)\n' - '\n' - ' Execute the *statement* (given as a string or a code object) ' - 'under\n' - ' debugger control. The debugger prompt appears before any ' - 'code is\n' - ' executed; you can set breakpoints and type "continue", or you ' - 'can\n' - ' step through the statement using "step" or "next" (all these\n' - ' commands are explained below). The optional *globals* and ' - '*locals*\n' - ' arguments specify the environment in which the code is ' - 'executed; by\n' - ' default the dictionary of the module "__main__" is used. ' - '(See the\n' - ' explanation of the built-in "exec()" or "eval()" functions.)\n' - '\n' - 'pdb.runeval(expression, globals=None, locals=None)\n' - '\n' - ' Evaluate the *expression* (given as a string or a code ' - 'object)\n' - ' under debugger control. When "runeval()" returns, it returns ' - 'the\n' - ' value of the expression. Otherwise this function is similar ' - 'to\n' - ' "run()".\n' - '\n' - 'pdb.runcall(function, *args, **kwds)\n' - '\n' - ' Call the *function* (a function or method object, not a ' - 'string)\n' - ' with the given arguments. When "runcall()" returns, it ' - 'returns\n' - ' whatever the function call returned. The debugger prompt ' - 'appears\n' - ' as soon as the function is entered.\n' - '\n' - 'pdb.set_trace()\n' - '\n' - ' Enter the debugger at the calling stack frame. This is ' - 'useful to\n' - ' hard-code a breakpoint at a given point in a program, even if ' - 'the\n' - ' code is not otherwise being debugged (e.g. when an assertion\n' - ' fails).\n' - '\n' - 'pdb.post_mortem(traceback=None)\n' - '\n' - ' Enter post-mortem debugging of the given *traceback* object. ' - 'If no\n' - ' *traceback* is given, it uses the one of the exception that ' - 'is\n' - ' currently being handled (an exception must be being handled ' - 'if the\n' - ' default is to be used).\n' - '\n' - 'pdb.pm()\n' - '\n' - ' Enter post-mortem debugging of the traceback found in\n' - ' "sys.last_traceback".\n' - '\n' - 'The "run*" functions and "set_trace()" are aliases for ' - 'instantiating\n' - 'the "Pdb" class and calling the method of the same name. If you ' - 'want\n' - 'to access further features, you have to do this yourself:\n' - '\n' - "class pdb.Pdb(completekey='tab', stdin=None, stdout=None, " - 'skip=None, nosigint=False, readrc=True)\n' - '\n' - ' "Pdb" is the debugger class.\n' - '\n' - ' The *completekey*, *stdin* and *stdout* arguments are passed ' - 'to the\n' - ' underlying "cmd.Cmd" class; see the description there.\n' - '\n' - ' The *skip* argument, if given, must be an iterable of ' - 'glob-style\n' - ' module name patterns. The debugger will not step into frames ' - 'that\n' - ' originate in a module that matches one of these patterns. ' - '[1]\n' - '\n' - ' By default, Pdb sets a handler for the SIGINT signal (which ' - 'is sent\n' - ' when the user presses "Ctrl-C" on the console) when you give ' - 'a\n' - ' "continue" command. This allows you to break into the ' - 'debugger\n' - ' again by pressing "Ctrl-C". If you want Pdb not to touch ' - 'the\n' - ' SIGINT handler, set *nosigint* to true.\n' - '\n' - ' The *readrc* argument defaults to true and controls whether ' - 'Pdb\n' - ' will load .pdbrc files from the filesystem.\n' - '\n' - ' Example call to enable tracing with *skip*:\n' - '\n' - " import pdb; pdb.Pdb(skip=['django.*']).set_trace()\n" - '\n' - ' New in version 3.1: The *skip* argument.\n' - '\n' - ' New in version 3.2: The *nosigint* argument. Previously, a ' - 'SIGINT\n' - ' handler was never set by Pdb.\n' - '\n' - ' Changed in version 3.6: The *readrc* argument.\n' - '\n' - ' run(statement, globals=None, locals=None)\n' - ' runeval(expression, globals=None, locals=None)\n' - ' runcall(function, *args, **kwds)\n' - ' set_trace()\n' - '\n' - ' See the documentation for the functions explained above.\n' - '\n' - '\n' - 'Debugger Commands\n' - '=================\n' - '\n' - 'The commands recognized by the debugger are listed below. Most\n' - 'commands can be abbreviated to one or two letters as indicated; ' - 'e.g.\n' - '"h(elp)" means that either "h" or "help" can be used to enter ' - 'the help\n' - 'command (but not "he" or "hel", nor "H" or "Help" or "HELP").\n' - 'Arguments to commands must be separated by whitespace (spaces ' - 'or\n' - 'tabs). Optional arguments are enclosed in square brackets ' - '("[]") in\n' - 'the command syntax; the square brackets must not be typed.\n' - 'Alternatives in the command syntax are separated by a vertical ' - 'bar\n' - '("|").\n' - '\n' - 'Entering a blank line repeats the last command entered. ' - 'Exception: if\n' - 'the last command was a "list" command, the next 11 lines are ' - 'listed.\n' - '\n' - 'Commands that the debugger doesn’t recognize are assumed to be ' - 'Python\n' - 'statements and are executed in the context of the program being\n' - 'debugged. Python statements can also be prefixed with an ' - 'exclamation\n' - 'point ("!"). This is a powerful way to inspect the program ' - 'being\n' - 'debugged; it is even possible to change a variable or call a ' - 'function.\n' - 'When an exception occurs in such a statement, the exception name ' - 'is\n' - 'printed but the debugger’s state is not changed.\n' - '\n' - 'The debugger supports aliases. Aliases can have parameters ' - 'which\n' - 'allows one a certain level of adaptability to the context under\n' - 'examination.\n' - '\n' - 'Multiple commands may be entered on a single line, separated by ' - '";;".\n' - '(A single ";" is not used as it is the separator for multiple ' - 'commands\n' - 'in a line that is passed to the Python parser.) No intelligence ' - 'is\n' - 'applied to separating the commands; the input is split at the ' - 'first\n' - '";;" pair, even if it is in the middle of a quoted string.\n' - '\n' - 'If a file ".pdbrc" exists in the user’s home directory or in ' - 'the\n' - 'current directory, it is read in and executed as if it had been ' - 'typed\n' - 'at the debugger prompt. This is particularly useful for ' - 'aliases. If\n' - 'both files exist, the one in the home directory is read first ' - 'and\n' - 'aliases defined there can be overridden by the local file.\n' - '\n' - 'Changed in version 3.2: ".pdbrc" can now contain commands that\n' - 'continue debugging, such as "continue" or "next". Previously, ' - 'these\n' - 'commands had no effect.\n' - '\n' - 'h(elp) [command]\n' - '\n' - ' Without argument, print the list of available commands. With ' - 'a\n' - ' *command* as argument, print help about that command. "help ' - 'pdb"\n' - ' displays the full documentation (the docstring of the "pdb"\n' - ' module). Since the *command* argument must be an identifier, ' - '"help\n' - ' exec" must be entered to get help on the "!" command.\n' - '\n' - 'w(here)\n' - '\n' - ' Print a stack trace, with the most recent frame at the ' - 'bottom. An\n' - ' arrow indicates the current frame, which determines the ' - 'context of\n' - ' most commands.\n' - '\n' - 'd(own) [count]\n' - '\n' - ' Move the current frame *count* (default one) levels down in ' - 'the\n' - ' stack trace (to a newer frame).\n' - '\n' - 'u(p) [count]\n' - '\n' - ' Move the current frame *count* (default one) levels up in the ' - 'stack\n' - ' trace (to an older frame).\n' - '\n' - 'b(reak) [([filename:]lineno | function) [, condition]]\n' - '\n' - ' With a *lineno* argument, set a break there in the current ' - 'file.\n' - ' With a *function* argument, set a break at the first ' - 'executable\n' - ' statement within that function. The line number may be ' - 'prefixed\n' - ' with a filename and a colon, to specify a breakpoint in ' - 'another\n' - ' file (probably one that hasn’t been loaded yet). The file ' - 'is\n' - ' searched on "sys.path". Note that each breakpoint is ' - 'assigned a\n' - ' number to which all the other breakpoint commands refer.\n' - '\n' - ' If a second argument is present, it is an expression which ' - 'must\n' - ' evaluate to true before the breakpoint is honored.\n' - '\n' - ' Without argument, list all breaks, including for each ' - 'breakpoint,\n' - ' the number of times that breakpoint has been hit, the ' - 'current\n' - ' ignore count, and the associated condition if any.\n' - '\n' - 'tbreak [([filename:]lineno | function) [, condition]]\n' - '\n' - ' Temporary breakpoint, which is removed automatically when it ' - 'is\n' - ' first hit. The arguments are the same as for "break".\n' - '\n' - 'cl(ear) [filename:lineno | bpnumber [bpnumber ...]]\n' - '\n' - ' With a *filename:lineno* argument, clear all the breakpoints ' - 'at\n' - ' this line. With a space separated list of breakpoint numbers, ' - 'clear\n' - ' those breakpoints. Without argument, clear all breaks (but ' - 'first\n' - ' ask confirmation).\n' - '\n' - 'disable [bpnumber [bpnumber ...]]\n' - '\n' - ' Disable the breakpoints given as a space separated list of\n' - ' breakpoint numbers. Disabling a breakpoint means it cannot ' - 'cause\n' - ' the program to stop execution, but unlike clearing a ' - 'breakpoint, it\n' - ' remains in the list of breakpoints and can be (re-)enabled.\n' - '\n' - 'enable [bpnumber [bpnumber ...]]\n' - '\n' - ' Enable the breakpoints specified.\n' - '\n' - 'ignore bpnumber [count]\n' - '\n' - ' Set the ignore count for the given breakpoint number. If ' - 'count is\n' - ' omitted, the ignore count is set to 0. A breakpoint becomes ' - 'active\n' - ' when the ignore count is zero. When non-zero, the count is\n' - ' decremented each time the breakpoint is reached and the ' - 'breakpoint\n' - ' is not disabled and any associated condition evaluates to ' - 'true.\n' - '\n' - 'condition bpnumber [condition]\n' - '\n' - ' Set a new *condition* for the breakpoint, an expression which ' - 'must\n' - ' evaluate to true before the breakpoint is honored. If ' - '*condition*\n' - ' is absent, any existing condition is removed; i.e., the ' - 'breakpoint\n' - ' is made unconditional.\n' - '\n' - 'commands [bpnumber]\n' - '\n' - ' Specify a list of commands for breakpoint number *bpnumber*. ' - 'The\n' - ' commands themselves appear on the following lines. Type a ' - 'line\n' - ' containing just "end" to terminate the commands. An example:\n' - '\n' - ' (Pdb) commands 1\n' - ' (com) p some_variable\n' - ' (com) end\n' - ' (Pdb)\n' - '\n' - ' To remove all commands from a breakpoint, type commands and ' - 'follow\n' - ' it immediately with "end"; that is, give no commands.\n' - '\n' - ' With no *bpnumber* argument, commands refers to the last ' - 'breakpoint\n' - ' set.\n' - '\n' - ' You can use breakpoint commands to start your program up ' - 'again.\n' - ' Simply use the continue command, or step, or any other ' - 'command that\n' - ' resumes execution.\n' - '\n' - ' Specifying any command resuming execution (currently ' - 'continue,\n' - ' step, next, return, jump, quit and their abbreviations) ' - 'terminates\n' - ' the command list (as if that command was immediately followed ' - 'by\n' - ' end). This is because any time you resume execution (even ' - 'with a\n' - ' simple next or step), you may encounter another ' - 'breakpoint—which\n' - ' could have its own command list, leading to ambiguities about ' - 'which\n' - ' list to execute.\n' - '\n' - ' If you use the ‘silent’ command in the command list, the ' - 'usual\n' - ' message about stopping at a breakpoint is not printed. This ' - 'may be\n' - ' desirable for breakpoints that are to print a specific ' - 'message and\n' - ' then continue. If none of the other commands print anything, ' - 'you\n' - ' see no sign that the breakpoint was reached.\n' - '\n' - 's(tep)\n' - '\n' - ' Execute the current line, stop at the first possible ' - 'occasion\n' - ' (either in a function that is called or on the next line in ' - 'the\n' - ' current function).\n' - '\n' - 'n(ext)\n' - '\n' - ' Continue execution until the next line in the current ' - 'function is\n' - ' reached or it returns. (The difference between "next" and ' - '"step"\n' - ' is that "step" stops inside a called function, while "next"\n' - ' executes called functions at (nearly) full speed, only ' - 'stopping at\n' - ' the next line in the current function.)\n' - '\n' - 'unt(il) [lineno]\n' - '\n' - ' Without argument, continue execution until the line with a ' - 'number\n' - ' greater than the current one is reached.\n' - '\n' - ' With a line number, continue execution until a line with a ' - 'number\n' - ' greater or equal to that is reached. In both cases, also ' - 'stop when\n' - ' the current frame returns.\n' - '\n' - ' Changed in version 3.2: Allow giving an explicit line ' - 'number.\n' - '\n' - 'r(eturn)\n' - '\n' - ' Continue execution until the current function returns.\n' - '\n' - 'c(ont(inue))\n' - '\n' - ' Continue execution, only stop when a breakpoint is ' - 'encountered.\n' - '\n' - 'j(ump) lineno\n' - '\n' - ' Set the next line that will be executed. Only available in ' - 'the\n' - ' bottom-most frame. This lets you jump back and execute code ' - 'again,\n' - ' or jump forward to skip code that you don’t want to run.\n' - '\n' - ' It should be noted that not all jumps are allowed – for ' - 'instance it\n' - ' is not possible to jump into the middle of a "for" loop or ' - 'out of a\n' - ' "finally" clause.\n' - '\n' - 'l(ist) [first[, last]]\n' - '\n' - ' List source code for the current file. Without arguments, ' - 'list 11\n' - ' lines around the current line or continue the previous ' - 'listing.\n' - ' With "." as argument, list 11 lines around the current line. ' - 'With\n' - ' one argument, list 11 lines around at that line. With two\n' - ' arguments, list the given range; if the second argument is ' - 'less\n' - ' than the first, it is interpreted as a count.\n' - '\n' - ' The current line in the current frame is indicated by "->". ' - 'If an\n' - ' exception is being debugged, the line where the exception ' - 'was\n' - ' originally raised or propagated is indicated by ">>", if it ' - 'differs\n' - ' from the current line.\n' - '\n' - ' New in version 3.2: The ">>" marker.\n' - '\n' - 'll | longlist\n' - '\n' - ' List all source code for the current function or frame.\n' - ' Interesting lines are marked as for "list".\n' - '\n' - ' New in version 3.2.\n' - '\n' - 'a(rgs)\n' - '\n' - ' Print the argument list of the current function.\n' - '\n' - 'p expression\n' - '\n' - ' Evaluate the *expression* in the current context and print ' - 'its\n' - ' value.\n' - '\n' - ' Note: "print()" can also be used, but is not a debugger ' - 'command —\n' - ' this executes the Python "print()" function.\n' - '\n' - 'pp expression\n' - '\n' - ' Like the "p" command, except the value of the expression is ' - 'pretty-\n' - ' printed using the "pprint" module.\n' - '\n' - 'whatis expression\n' - '\n' - ' Print the type of the *expression*.\n' - '\n' - 'source expression\n' - '\n' - ' Try to get source code for the given object and display it.\n' - '\n' - ' New in version 3.2.\n' - '\n' - 'display [expression]\n' - '\n' - ' Display the value of the expression if it changed, each time\n' - ' execution stops in the current frame.\n' - '\n' - ' Without expression, list all display expressions for the ' - 'current\n' - ' frame.\n' - '\n' - ' New in version 3.2.\n' - '\n' - 'undisplay [expression]\n' - '\n' - ' Do not display the expression any more in the current frame.\n' - ' Without expression, clear all display expressions for the ' - 'current\n' - ' frame.\n' - '\n' - ' New in version 3.2.\n' - '\n' - 'interact\n' - '\n' - ' Start an interactive interpreter (using the "code" module) ' - 'whose\n' - ' global namespace contains all the (global and local) names ' - 'found in\n' - ' the current scope.\n' - '\n' - ' New in version 3.2.\n' - '\n' - 'alias [name [command]]\n' - '\n' - ' Create an alias called *name* that executes *command*. The ' - 'command\n' - ' must *not* be enclosed in quotes. Replaceable parameters can ' - 'be\n' - ' indicated by "%1", "%2", and so on, while "%*" is replaced by ' - 'all\n' - ' the parameters. If no command is given, the current alias ' - 'for\n' - ' *name* is shown. If no arguments are given, all aliases are ' - 'listed.\n' - '\n' - ' Aliases may be nested and can contain anything that can be ' - 'legally\n' - ' typed at the pdb prompt. Note that internal pdb commands ' - '*can* be\n' - ' overridden by aliases. Such a command is then hidden until ' - 'the\n' - ' alias is removed. Aliasing is recursively applied to the ' - 'first\n' - ' word of the command line; all other words in the line are ' - 'left\n' - ' alone.\n' - '\n' - ' As an example, here are two useful aliases (especially when ' - 'placed\n' - ' in the ".pdbrc" file):\n' - '\n' - ' # Print instance variables (usage "pi classInst")\n' - ' alias pi for k in %1.__dict__.keys(): ' - 'print("%1.",k,"=",%1.__dict__[k])\n' - ' # Print instance variables in self\n' - ' alias ps pi self\n' - '\n' - 'unalias name\n' - '\n' - ' Delete the specified alias.\n' - '\n' - '! statement\n' - '\n' - ' Execute the (one-line) *statement* in the context of the ' - 'current\n' - ' stack frame. The exclamation point can be omitted unless the ' - 'first\n' - ' word of the statement resembles a debugger command. To set ' - 'a\n' - ' global variable, you can prefix the assignment command with ' - 'a\n' - ' "global" statement on the same line, e.g.:\n' - '\n' - " (Pdb) global list_options; list_options = ['-l']\n" - ' (Pdb)\n' - '\n' - 'run [args ...]\n' - 'restart [args ...]\n' - '\n' - ' Restart the debugged Python program. If an argument is ' - 'supplied,\n' - ' it is split with "shlex" and the result is used as the new\n' - ' "sys.argv". History, breakpoints, actions and debugger ' - 'options are\n' - ' preserved. "restart" is an alias for "run".\n' - '\n' - 'q(uit)\n' - '\n' - ' Quit from the debugger. The program being executed is ' - 'aborted.\n' - '\n' - '-[ Footnotes ]-\n' - '\n' - '[1] Whether a frame is considered to originate in a certain ' - 'module\n' - ' is determined by the "__name__" in the frame globals.\n', - 'del': 'The "del" statement\n' - '*******************\n' - '\n' - ' del_stmt ::= "del" target_list\n' - '\n' - 'Deletion is recursively defined very similar to the way assignment ' - 'is\n' - 'defined. Rather than spelling it out in full details, here are some\n' - 'hints.\n' - '\n' - 'Deletion of a target list recursively deletes each target, from left\n' - 'to right.\n' - '\n' - 'Deletion of a name removes the binding of that name from the local ' - 'or\n' - 'global namespace, depending on whether the name occurs in a "global"\n' - 'statement in the same code block. If the name is unbound, a\n' - '"NameError" exception will be raised.\n' - '\n' - 'Deletion of attribute references, subscriptions and slicings is ' - 'passed\n' - 'to the primary object involved; deletion of a slicing is in general\n' - 'equivalent to assignment of an empty slice of the right type (but ' - 'even\n' - 'this is determined by the sliced object).\n' - '\n' - 'Changed in version 3.2: Previously it was illegal to delete a name\n' - 'from the local namespace if it occurs as a free variable in a nested\n' - 'block.\n', - 'dict': 'Dictionary displays\n' - '*******************\n' - '\n' - 'A dictionary display is a possibly empty series of key/datum pairs\n' - 'enclosed in curly braces:\n' - '\n' - ' dict_display ::= "{" [key_datum_list | dict_comprehension] ' - '"}"\n' - ' key_datum_list ::= key_datum ("," key_datum)* [","]\n' - ' key_datum ::= expression ":" expression | "**" or_expr\n' - ' dict_comprehension ::= expression ":" expression comp_for\n' - '\n' - 'A dictionary display yields a new dictionary object.\n' - '\n' - 'If a comma-separated sequence of key/datum pairs is given, they are\n' - 'evaluated from left to right to define the entries of the ' - 'dictionary:\n' - 'each key object is used as a key into the dictionary to store the\n' - 'corresponding datum. This means that you can specify the same key\n' - 'multiple times in the key/datum list, and the final dictionary’s ' - 'value\n' - 'for that key will be the last one given.\n' - '\n' - 'A double asterisk "**" denotes *dictionary unpacking*. Its operand\n' - 'must be a *mapping*. Each mapping item is added to the new\n' - 'dictionary. Later values replace values already set by earlier\n' - 'key/datum pairs and earlier dictionary unpackings.\n' - '\n' - 'New in version 3.5: Unpacking into dictionary displays, originally\n' - 'proposed by **PEP 448**.\n' - '\n' - 'A dict comprehension, in contrast to list and set comprehensions,\n' - 'needs two expressions separated with a colon followed by the usual\n' - '“for” and “if” clauses. When the comprehension is run, the ' - 'resulting\n' - 'key and value elements are inserted in the new dictionary in the ' - 'order\n' - 'they are produced.\n' - '\n' - 'Restrictions on the types of the key values are listed earlier in\n' - 'section The standard type hierarchy. (To summarize, the key type\n' - 'should be *hashable*, which excludes all mutable objects.) Clashes\n' - 'between duplicate keys are not detected; the last datum (textually\n' - 'rightmost in the display) stored for a given key value prevails.\n', - 'dynamic-features': 'Interaction with dynamic features\n' - '*********************************\n' + 'The "^" operator yields the bitwise XOR (exclusive OR) of its\n' + 'arguments, which must be integers or one of them must be a ' + 'custom\n' + 'object overriding "__xor__()" or "__rxor__()" special methods.\n' '\n' - 'Name resolution of free variables occurs at runtime, not ' - 'at compile\n' - 'time. This means that the following code will print 42:\n' - '\n' - ' i = 10\n' - ' def f():\n' - ' print(i)\n' - ' i = 42\n' - ' f()\n' - '\n' - 'The "eval()" and "exec()" functions do not have access ' - 'to the full\n' - 'environment for resolving names. Names may be resolved ' - 'in the local\n' - 'and global namespaces of the caller. Free variables are ' - 'not resolved\n' - 'in the nearest enclosing namespace, but in the global ' - 'namespace. [1]\n' - 'The "exec()" and "eval()" functions have optional ' - 'arguments to\n' - 'override the global and local namespace. If only one ' - 'namespace is\n' - 'specified, it is used for both.\n', - 'else': 'The "if" statement\n' - '******************\n' - '\n' - 'The "if" statement is used for conditional execution:\n' - '\n' - ' if_stmt ::= "if" expression ":" suite\n' - ' ("elif" expression ":" suite)*\n' - ' ["else" ":" suite]\n' - '\n' - 'It selects exactly one of the suites by evaluating the expressions ' - 'one\n' - 'by one until one is found to be true (see section Boolean ' - 'operations\n' - 'for the definition of true and false); then that suite is executed\n' - '(and no other part of the "if" statement is executed or evaluated).\n' - 'If all expressions are false, the suite of the "else" clause, if\n' - 'present, is executed.\n', - 'exceptions': 'Exceptions\n' - '**********\n' - '\n' - 'Exceptions are a means of breaking out of the normal flow of ' - 'control\n' - 'of a code block in order to handle errors or other ' - 'exceptional\n' - 'conditions. An exception is *raised* at the point where the ' - 'error is\n' - 'detected; it may be *handled* by the surrounding code block or ' - 'by any\n' - 'code block that directly or indirectly invoked the code block ' - 'where\n' - 'the error occurred.\n' - '\n' - 'The Python interpreter raises an exception when it detects a ' - 'run-time\n' - 'error (such as division by zero). A Python program can also\n' - 'explicitly raise an exception with the "raise" statement. ' - 'Exception\n' - 'handlers are specified with the "try" … "except" statement. ' - 'The\n' - '"finally" clause of such a statement can be used to specify ' - 'cleanup\n' - 'code which does not handle the exception, but is executed ' - 'whether an\n' - 'exception occurred or not in the preceding code.\n' - '\n' - 'Python uses the “termination” model of error handling: an ' - 'exception\n' - 'handler can find out what happened and continue execution at ' - 'an outer\n' - 'level, but it cannot repair the cause of the error and retry ' - 'the\n' - 'failing operation (except by re-entering the offending piece ' - 'of code\n' - 'from the top).\n' - '\n' - 'When an exception is not handled at all, the interpreter ' - 'terminates\n' - 'execution of the program, or returns to its interactive main ' - 'loop. In\n' - 'either case, it prints a stack backtrace, except when the ' - 'exception is\n' - '"SystemExit".\n' - '\n' - 'Exceptions are identified by class instances. The "except" ' - 'clause is\n' - 'selected depending on the class of the instance: it must ' - 'reference the\n' - 'class of the instance or a base class thereof. The instance ' - 'can be\n' - 'received by the handler and can carry additional information ' - 'about the\n' - 'exceptional condition.\n' - '\n' - 'Note: Exception messages are not part of the Python API. ' - 'Their\n' - ' contents may change from one version of Python to the next ' - 'without\n' - ' warning and should not be relied on by code which will run ' - 'under\n' - ' multiple versions of the interpreter.\n' - '\n' - 'See also the description of the "try" statement in section The ' - 'try\n' - 'statement and "raise" statement in section The raise ' - 'statement.\n' - '\n' - '-[ Footnotes ]-\n' - '\n' - '[1] This limitation occurs because the code that is executed ' - 'by\n' - ' these operations is not available at the time the module ' - 'is\n' - ' compiled.\n', - 'execmodel': 'Execution model\n' - '***************\n' - '\n' - '\n' - 'Structure of a program\n' - '======================\n' - '\n' - 'A Python program is constructed from code blocks. A *block* is ' - 'a piece\n' - 'of Python program text that is executed as a unit. The ' - 'following are\n' - 'blocks: a module, a function body, and a class definition. ' - 'Each\n' - 'command typed interactively is a block. A script file (a file ' - 'given\n' - 'as standard input to the interpreter or specified as a command ' - 'line\n' - 'argument to the interpreter) is a code block. A script command ' - '(a\n' - 'command specified on the interpreter command line with the ' - '"-c"\n' - 'option) is a code block. The string argument passed to the ' - 'built-in\n' - 'functions "eval()" and "exec()" is a code block.\n' - '\n' - 'A code block is executed in an *execution frame*. A frame ' - 'contains\n' - 'some administrative information (used for debugging) and ' - 'determines\n' - 'where and how execution continues after the code block’s ' - 'execution has\n' - 'completed.\n' - '\n' - '\n' - 'Naming and binding\n' - '==================\n' - '\n' - '\n' - 'Binding of names\n' - '----------------\n' - '\n' - '*Names* refer to objects. Names are introduced by name ' - 'binding\n' - 'operations.\n' - '\n' - 'The following constructs bind names: formal parameters to ' - 'functions,\n' - '"import" statements, class and function definitions (these bind ' - 'the\n' - 'class or function name in the defining block), and targets that ' - 'are\n' - 'identifiers if occurring in an assignment, "for" loop header, ' - 'or after\n' - '"as" in a "with" statement or "except" clause. The "import" ' - 'statement\n' - 'of the form "from ... import *" binds all names defined in the\n' - 'imported module, except those beginning with an underscore. ' - 'This form\n' - 'may only be used at the module level.\n' - '\n' - 'A target occurring in a "del" statement is also considered ' - 'bound for\n' - 'this purpose (though the actual semantics are to unbind the ' - 'name).\n' - '\n' - 'Each assignment or import statement occurs within a block ' - 'defined by a\n' - 'class or function definition or at the module level (the ' - 'top-level\n' - 'code block).\n' - '\n' - 'If a name is bound in a block, it is a local variable of that ' - 'block,\n' - 'unless declared as "nonlocal" or "global". If a name is bound ' - 'at the\n' - 'module level, it is a global variable. (The variables of the ' - 'module\n' - 'code block are local and global.) If a variable is used in a ' - 'code\n' - 'block but not defined there, it is a *free variable*.\n' - '\n' - 'Each occurrence of a name in the program text refers to the ' - '*binding*\n' - 'of that name established by the following name resolution ' - 'rules.\n' - '\n' - '\n' - 'Resolution of names\n' - '-------------------\n' - '\n' - 'A *scope* defines the visibility of a name within a block. If ' - 'a local\n' - 'variable is defined in a block, its scope includes that block. ' - 'If the\n' - 'definition occurs in a function block, the scope extends to any ' - 'blocks\n' - 'contained within the defining one, unless a contained block ' - 'introduces\n' - 'a different binding for the name.\n' - '\n' - 'When a name is used in a code block, it is resolved using the ' - 'nearest\n' - 'enclosing scope. The set of all such scopes visible to a code ' - 'block\n' - 'is called the block’s *environment*.\n' - '\n' - 'When a name is not found at all, a "NameError" exception is ' - 'raised. If\n' - 'the current scope is a function scope, and the name refers to a ' - 'local\n' - 'variable that has not yet been bound to a value at the point ' - 'where the\n' - 'name is used, an "UnboundLocalError" exception is raised.\n' - '"UnboundLocalError" is a subclass of "NameError".\n' - '\n' - 'If a name binding operation occurs anywhere within a code ' - 'block, all\n' - 'uses of the name within the block are treated as references to ' - 'the\n' - 'current block. This can lead to errors when a name is used ' - 'within a\n' - 'block before it is bound. This rule is subtle. Python lacks\n' - 'declarations and allows name binding operations to occur ' - 'anywhere\n' - 'within a code block. The local variables of a code block can ' - 'be\n' - 'determined by scanning the entire text of the block for name ' - 'binding\n' - 'operations.\n' - '\n' - 'If the "global" statement occurs within a block, all uses of ' - 'the name\n' - 'specified in the statement refer to the binding of that name in ' - 'the\n' - 'top-level namespace. Names are resolved in the top-level ' - 'namespace by\n' - 'searching the global namespace, i.e. the namespace of the ' - 'module\n' - 'containing the code block, and the builtins namespace, the ' - 'namespace\n' - 'of the module "builtins". The global namespace is searched ' - 'first. If\n' - 'the name is not found there, the builtins namespace is ' - 'searched. The\n' - '"global" statement must precede all uses of the name.\n' - '\n' - 'The "global" statement has the same scope as a name binding ' - 'operation\n' - 'in the same block. If the nearest enclosing scope for a free ' - 'variable\n' - 'contains a global statement, the free variable is treated as a ' - 'global.\n' - '\n' - 'The "nonlocal" statement causes corresponding names to refer ' - 'to\n' - 'previously bound variables in the nearest enclosing function ' - 'scope.\n' - '"SyntaxError" is raised at compile time if the given name does ' - 'not\n' - 'exist in any enclosing function scope.\n' - '\n' - 'The namespace for a module is automatically created the first ' - 'time a\n' - 'module is imported. The main module for a script is always ' - 'called\n' - '"__main__".\n' - '\n' - 'Class definition blocks and arguments to "exec()" and "eval()" ' - 'are\n' - 'special in the context of name resolution. A class definition ' - 'is an\n' - 'executable statement that may use and define names. These ' - 'references\n' - 'follow the normal rules for name resolution with an exception ' - 'that\n' - 'unbound local variables are looked up in the global namespace. ' - 'The\n' - 'namespace of the class definition becomes the attribute ' - 'dictionary of\n' - 'the class. The scope of names defined in a class block is ' - 'limited to\n' - 'the class block; it does not extend to the code blocks of ' - 'methods –\n' - 'this includes comprehensions and generator expressions since ' - 'they are\n' - 'implemented using a function scope. This means that the ' - 'following\n' - 'will fail:\n' - '\n' - ' class A:\n' - ' a = 42\n' - ' b = list(a + i for i in range(10))\n' - '\n' - '\n' - 'Builtins and restricted execution\n' - '---------------------------------\n' - '\n' - '**CPython implementation detail:** Users should not touch\n' - '"__builtins__"; it is strictly an implementation detail. ' - 'Users\n' - 'wanting to override values in the builtins namespace should ' - '"import"\n' - 'the "builtins" module and modify its attributes appropriately.\n' - '\n' - 'The builtins namespace associated with the execution of a code ' - 'block\n' - 'is actually found by looking up the name "__builtins__" in its ' - 'global\n' - 'namespace; this should be a dictionary or a module (in the ' - 'latter case\n' - 'the module’s dictionary is used). By default, when in the ' - '"__main__"\n' - 'module, "__builtins__" is the built-in module "builtins"; when ' - 'in any\n' - 'other module, "__builtins__" is an alias for the dictionary of ' - 'the\n' - '"builtins" module itself.\n' - '\n' - '\n' - 'Interaction with dynamic features\n' - '---------------------------------\n' - '\n' - 'Name resolution of free variables occurs at runtime, not at ' - 'compile\n' - 'time. This means that the following code will print 42:\n' - '\n' - ' i = 10\n' - ' def f():\n' - ' print(i)\n' - ' i = 42\n' - ' f()\n' - '\n' - 'The "eval()" and "exec()" functions do not have access to the ' - 'full\n' - 'environment for resolving names. Names may be resolved in the ' - 'local\n' - 'and global namespaces of the caller. Free variables are not ' - 'resolved\n' - 'in the nearest enclosing namespace, but in the global ' - 'namespace. [1]\n' - 'The "exec()" and "eval()" functions have optional arguments to\n' - 'override the global and local namespace. If only one namespace ' - 'is\n' - 'specified, it is used for both.\n' - '\n' - '\n' - 'Exceptions\n' - '==========\n' - '\n' - 'Exceptions are a means of breaking out of the normal flow of ' - 'control\n' - 'of a code block in order to handle errors or other exceptional\n' - 'conditions. An exception is *raised* at the point where the ' - 'error is\n' - 'detected; it may be *handled* by the surrounding code block or ' - 'by any\n' - 'code block that directly or indirectly invoked the code block ' - 'where\n' - 'the error occurred.\n' - '\n' - 'The Python interpreter raises an exception when it detects a ' - 'run-time\n' - 'error (such as division by zero). A Python program can also\n' - 'explicitly raise an exception with the "raise" statement. ' - 'Exception\n' - 'handlers are specified with the "try" … "except" statement. ' - 'The\n' - '"finally" clause of such a statement can be used to specify ' - 'cleanup\n' - 'code which does not handle the exception, but is executed ' - 'whether an\n' - 'exception occurred or not in the preceding code.\n' - '\n' - 'Python uses the “termination” model of error handling: an ' - 'exception\n' - 'handler can find out what happened and continue execution at an ' - 'outer\n' - 'level, but it cannot repair the cause of the error and retry ' - 'the\n' - 'failing operation (except by re-entering the offending piece of ' - 'code\n' - 'from the top).\n' - '\n' - 'When an exception is not handled at all, the interpreter ' - 'terminates\n' - 'execution of the program, or returns to its interactive main ' - 'loop. In\n' - 'either case, it prints a stack backtrace, except when the ' - 'exception is\n' - '"SystemExit".\n' - '\n' - 'Exceptions are identified by class instances. The "except" ' - 'clause is\n' - 'selected depending on the class of the instance: it must ' - 'reference the\n' - 'class of the instance or a base class thereof. The instance ' - 'can be\n' - 'received by the handler and can carry additional information ' - 'about the\n' - 'exceptional condition.\n' - '\n' - 'Note: Exception messages are not part of the Python API. ' - 'Their\n' - ' contents may change from one version of Python to the next ' - 'without\n' - ' warning and should not be relied on by code which will run ' - 'under\n' - ' multiple versions of the interpreter.\n' - '\n' - 'See also the description of the "try" statement in section The ' - 'try\n' - 'statement and "raise" statement in section The raise ' - 'statement.\n' - '\n' - '-[ Footnotes ]-\n' - '\n' - '[1] This limitation occurs because the code that is executed ' - 'by\n' - ' these operations is not available at the time the module ' - 'is\n' - ' compiled.\n', - 'exprlists': 'Expression lists\n' - '****************\n' - '\n' - ' expression_list ::= expression ("," expression)* [","]\n' - ' starred_list ::= starred_item ("," starred_item)* ' - '[","]\n' - ' starred_expression ::= expression | (starred_item ",")* ' - '[starred_item]\n' - ' starred_item ::= expression | "*" or_expr\n' - '\n' - 'Except when part of a list or set display, an expression list\n' - 'containing at least one comma yields a tuple. The length of ' - 'the tuple\n' - 'is the number of expressions in the list. The expressions are\n' - 'evaluated from left to right.\n' - '\n' - 'An asterisk "*" denotes *iterable unpacking*. Its operand must ' - 'be an\n' - '*iterable*. The iterable is expanded into a sequence of items, ' - 'which\n' - 'are included in the new tuple, list, or set, at the site of ' - 'the\n' - 'unpacking.\n' - '\n' - 'New in version 3.5: Iterable unpacking in expression lists, ' - 'originally\n' - 'proposed by **PEP 448**.\n' - '\n' - 'The trailing comma is required only to create a single tuple ' - '(a.k.a. a\n' - '*singleton*); it is optional in all other cases. A single ' - 'expression\n' - 'without a trailing comma doesn’t create a tuple, but rather ' - 'yields the\n' - 'value of that expression. (To create an empty tuple, use an ' - 'empty pair\n' - 'of parentheses: "()".)\n', - 'floating': 'Floating point literals\n' - '***********************\n' - '\n' - 'Floating point literals are described by the following lexical\n' - 'definitions:\n' - '\n' - ' floatnumber ::= pointfloat | exponentfloat\n' - ' pointfloat ::= [digitpart] fraction | digitpart "."\n' - ' exponentfloat ::= (digitpart | pointfloat) exponent\n' - ' digitpart ::= digit (["_"] digit)*\n' - ' fraction ::= "." digitpart\n' - ' exponent ::= ("e" | "E") ["+" | "-"] digitpart\n' - '\n' - 'Note that the integer and exponent parts are always interpreted ' - 'using\n' - 'radix 10. For example, "077e010" is legal, and denotes the same ' - 'number\n' - 'as "77e10". The allowed range of floating point literals is\n' - 'implementation-dependent. As in integer literals, underscores ' - 'are\n' - 'supported for digit grouping.\n' - '\n' - 'Some examples of floating point literals:\n' - '\n' - ' 3.14 10. .001 1e100 3.14e-10 0e0 ' - '3.14_15_93\n' - '\n' - 'Changed in version 3.6: Underscores are now allowed for ' - 'grouping\n' - 'purposes in literals.\n', - 'for': 'The "for" statement\n' - '*******************\n' - '\n' - 'The "for" statement is used to iterate over the elements of a ' - 'sequence\n' - '(such as a string, tuple or list) or other iterable object:\n' - '\n' - ' for_stmt ::= "for" target_list "in" expression_list ":" suite\n' - ' ["else" ":" suite]\n' - '\n' - 'The expression list is evaluated once; it should yield an iterable\n' - 'object. An iterator is created for the result of the\n' - '"expression_list". The suite is then executed once for each item\n' - 'provided by the iterator, in the order returned by the iterator. ' - 'Each\n' - 'item in turn is assigned to the target list using the standard rules\n' - 'for assignments (see Assignment statements), and then the suite is\n' - 'executed. When the items are exhausted (which is immediately when ' - 'the\n' - 'sequence is empty or an iterator raises a "StopIteration" ' - 'exception),\n' - 'the suite in the "else" clause, if present, is executed, and the ' - 'loop\n' - 'terminates.\n' - '\n' - 'A "break" statement executed in the first suite terminates the loop\n' - 'without executing the "else" clause’s suite. A "continue" statement\n' - 'executed in the first suite skips the rest of the suite and ' - 'continues\n' - 'with the next item, or with the "else" clause if there is no next\n' - 'item.\n' - '\n' - 'The for-loop makes assignments to the variables(s) in the target ' - 'list.\n' - 'This overwrites all previous assignments to those variables ' - 'including\n' - 'those made in the suite of the for-loop:\n' - '\n' - ' for i in range(10):\n' - ' print(i)\n' - ' i = 5 # this will not affect the for-loop\n' - ' # because i will be overwritten with the ' - 'next\n' - ' # index in the range\n' - '\n' - 'Names in the target list are not deleted when the loop is finished,\n' - 'but if the sequence is empty, they will not have been assigned to at\n' - 'all by the loop. Hint: the built-in function "range()" returns an\n' - 'iterator of integers suitable to emulate the effect of Pascal’s "for ' - 'i\n' - ':= a to b do"; e.g., "list(range(3))" returns the list "[0, 1, 2]".\n' - '\n' - 'Note: There is a subtlety when the sequence is being modified by the\n' - ' loop (this can only occur for mutable sequences, e.g. lists). An\n' - ' internal counter is used to keep track of which item is used next,\n' - ' and this is incremented on each iteration. When this counter has\n' - ' reached the length of the sequence the loop terminates. This ' - 'means\n' - ' that if the suite deletes the current (or a previous) item from ' - 'the\n' - ' sequence, the next item will be skipped (since it gets the index ' - 'of\n' - ' the current item which has already been treated). Likewise, if ' - 'the\n' - ' suite inserts an item in the sequence before the current item, the\n' - ' current item will be treated again the next time through the loop.\n' - ' This can lead to nasty bugs that can be avoided by making a\n' - ' temporary copy using a slice of the whole sequence, e.g.,\n' - '\n' - ' for x in a[:]:\n' - ' if x < 0: a.remove(x)\n', - 'formatstrings': 'Format String Syntax\n' - '********************\n' - '\n' - 'The "str.format()" method and the "Formatter" class share ' - 'the same\n' - 'syntax for format strings (although in the case of ' - '"Formatter",\n' - 'subclasses can define their own format string syntax). The ' - 'syntax is\n' - 'related to that of formatted string literals, but there ' - 'are\n' - 'differences.\n' - '\n' - 'Format strings contain “replacement fields” surrounded by ' - 'curly braces\n' - '"{}". Anything that is not contained in braces is ' - 'considered literal\n' - 'text, which is copied unchanged to the output. If you need ' - 'to include\n' - 'a brace character in the literal text, it can be escaped by ' - 'doubling:\n' - '"{{" and "}}".\n' - '\n' - 'The grammar for a replacement field is as follows:\n' - '\n' - ' replacement_field ::= "{" [field_name] ["!" ' - 'conversion] [":" format_spec] "}"\n' - ' field_name ::= arg_name ("." attribute_name | ' - '"[" element_index "]")*\n' - ' arg_name ::= [identifier | digit+]\n' - ' attribute_name ::= identifier\n' - ' element_index ::= digit+ | index_string\n' - ' index_string ::= +\n' - ' conversion ::= "r" | "s" | "a"\n' - ' format_spec ::= \n' - '\n' - 'In less formal terms, the replacement field can start with ' - 'a\n' - '*field_name* that specifies the object whose value is to be ' - 'formatted\n' - 'and inserted into the output instead of the replacement ' - 'field. The\n' - '*field_name* is optionally followed by a *conversion* ' - 'field, which is\n' - 'preceded by an exclamation point "\'!\'", and a ' - '*format_spec*, which is\n' - 'preceded by a colon "\':\'". These specify a non-default ' - 'format for the\n' - 'replacement value.\n' - '\n' - 'See also the Format Specification Mini-Language section.\n' - '\n' - 'The *field_name* itself begins with an *arg_name* that is ' - 'either a\n' - 'number or a keyword. If it’s a number, it refers to a ' - 'positional\n' - 'argument, and if it’s a keyword, it refers to a named ' - 'keyword\n' - 'argument. If the numerical arg_names in a format string ' - 'are 0, 1, 2,\n' - '… in sequence, they can all be omitted (not just some) and ' - 'the numbers\n' - '0, 1, 2, … will be automatically inserted in that order. ' - 'Because\n' - '*arg_name* is not quote-delimited, it is not possible to ' - 'specify\n' - 'arbitrary dictionary keys (e.g., the strings "\'10\'" or ' - '"\':-]\'") within\n' - 'a format string. The *arg_name* can be followed by any ' - 'number of index\n' - 'or attribute expressions. An expression of the form ' - '"\'.name\'" selects\n' - 'the named attribute using "getattr()", while an expression ' - 'of the form\n' - '"\'[index]\'" does an index lookup using "__getitem__()".\n' - '\n' - 'Changed in version 3.1: The positional argument specifiers ' - 'can be\n' - 'omitted for "str.format()", so "\'{} {}\'.format(a, b)" is ' - 'equivalent to\n' - '"\'{0} {1}\'.format(a, b)".\n' - '\n' - 'Changed in version 3.4: The positional argument specifiers ' - 'can be\n' - 'omitted for "Formatter".\n' - '\n' - 'Some simple format string examples:\n' - '\n' - ' "First, thou shalt count to {0}" # References first ' - 'positional argument\n' - ' "Bring me a {}" # Implicitly ' - 'references the first positional argument\n' - ' "From {} to {}" # Same as "From {0} to ' - '{1}"\n' - ' "My quest is {name}" # References keyword ' - "argument 'name'\n" - ' "Weight in tons {0.weight}" # \'weight\' attribute ' - 'of first positional arg\n' - ' "Units destroyed: {players[0]}" # First element of ' - "keyword argument 'players'.\n" - '\n' - 'The *conversion* field causes a type coercion before ' - 'formatting.\n' - 'Normally, the job of formatting a value is done by the ' - '"__format__()"\n' - 'method of the value itself. However, in some cases it is ' - 'desirable to\n' - 'force a type to be formatted as a string, overriding its ' - 'own\n' - 'definition of formatting. By converting the value to a ' - 'string before\n' - 'calling "__format__()", the normal formatting logic is ' - 'bypassed.\n' - '\n' - 'Three conversion flags are currently supported: "\'!s\'" ' - 'which calls\n' - '"str()" on the value, "\'!r\'" which calls "repr()" and ' - '"\'!a\'" which\n' - 'calls "ascii()".\n' - '\n' - 'Some examples:\n' - '\n' - ' "Harold\'s a clever {0!s}" # Calls str() on the ' - 'argument first\n' - ' "Bring out the holy {name!r}" # Calls repr() on the ' - 'argument first\n' - ' "More {!a}" # Calls ascii() on the ' - 'argument first\n' - '\n' - 'The *format_spec* field contains a specification of how the ' - 'value\n' - 'should be presented, including such details as field width, ' - 'alignment,\n' - 'padding, decimal precision and so on. Each value type can ' - 'define its\n' - 'own “formatting mini-language” or interpretation of the ' - '*format_spec*.\n' - '\n' - 'Most built-in types support a common formatting ' - 'mini-language, which\n' - 'is described in the next section.\n' - '\n' - 'A *format_spec* field can also include nested replacement ' - 'fields\n' - 'within it. These nested replacement fields may contain a ' - 'field name,\n' - 'conversion flag and format specification, but deeper ' - 'nesting is not\n' - 'allowed. The replacement fields within the format_spec ' - 'are\n' - 'substituted before the *format_spec* string is interpreted. ' - 'This\n' - 'allows the formatting of a value to be dynamically ' - 'specified.\n' - '\n' - 'See the Format examples section for some examples.\n' - '\n' - '\n' - 'Format Specification Mini-Language\n' - '==================================\n' - '\n' - '“Format specifications” are used within replacement fields ' - 'contained\n' - 'within a format string to define how individual values are ' - 'presented\n' - '(see Format String Syntax and Formatted string literals). ' - 'They can\n' - 'also be passed directly to the built-in "format()" ' - 'function. Each\n' - 'formattable type may define how the format specification is ' - 'to be\n' - 'interpreted.\n' - '\n' - 'Most built-in types implement the following options for ' - 'format\n' - 'specifications, although some of the formatting options are ' - 'only\n' - 'supported by the numeric types.\n' - '\n' - 'A general convention is that an empty format string ("""") ' - 'produces\n' - 'the same result as if you had called "str()" on the value. ' - 'A non-empty\n' - 'format string typically modifies the result.\n' - '\n' - 'The general form of a *standard format specifier* is:\n' - '\n' - ' format_spec ::= ' - '[[fill]align][sign][#][0][width][grouping_option][.precision][type]\n' - ' fill ::= \n' - ' align ::= "<" | ">" | "=" | "^"\n' - ' sign ::= "+" | "-" | " "\n' - ' width ::= digit+\n' - ' grouping_option ::= "_" | ","\n' - ' precision ::= digit+\n' - ' type ::= "b" | "c" | "d" | "e" | "E" | "f" | ' - '"F" | "g" | "G" | "n" | "o" | "s" | "x" | "X" | "%"\n' - '\n' - 'If a valid *align* value is specified, it can be preceded ' - 'by a *fill*\n' - 'character that can be any character and defaults to a space ' - 'if\n' - 'omitted. It is not possible to use a literal curly brace ' - '(“"{"” or\n' - '“"}"”) as the *fill* character in a formatted string ' - 'literal or when\n' - 'using the "str.format()" method. However, it is possible ' - 'to insert a\n' - 'curly brace with a nested replacement field. This ' - 'limitation doesn’t\n' - 'affect the "format()" function.\n' - '\n' - 'The meaning of the various alignment options is as ' - 'follows:\n' - '\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | Option | ' - 'Meaning ' - '|\n' - ' ' - '+===========+============================================================+\n' - ' | "\'<\'" | Forces the field to be left-aligned ' - 'within the available |\n' - ' | | space (this is the default for most ' - 'objects). |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | "\'>\'" | Forces the field to be right-aligned ' - 'within the available |\n' - ' | | space (this is the default for ' - 'numbers). |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | "\'=\'" | Forces the padding to be placed after ' - 'the sign (if any) |\n' - ' | | but before the digits. This is used for ' - 'printing fields |\n' - ' | | in the form ‘+000000120’. This alignment ' - 'option is only |\n' - ' | | valid for numeric types. It becomes the ' - 'default when ‘0’ |\n' - ' | | immediately precedes the field ' - 'width. |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | "\'^\'" | Forces the field to be centered within ' - 'the available |\n' - ' | | ' - 'space. ' - '|\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - '\n' - 'Note that unless a minimum field width is defined, the ' - 'field width\n' - 'will always be the same size as the data to fill it, so ' - 'that the\n' - 'alignment option has no meaning in this case.\n' - '\n' - 'The *sign* option is only valid for number types, and can ' - 'be one of\n' - 'the following:\n' - '\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | Option | ' - 'Meaning ' - '|\n' - ' ' - '+===========+============================================================+\n' - ' | "\'+\'" | indicates that a sign should be used for ' - 'both positive as |\n' - ' | | well as negative ' - 'numbers. |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | "\'-\'" | indicates that a sign should be used ' - 'only for negative |\n' - ' | | numbers (this is the default ' - 'behavior). |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | space | indicates that a leading space should be ' - 'used on positive |\n' - ' | | numbers, and a minus sign on negative ' - 'numbers. |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - '\n' - 'The "\'#\'" option causes the “alternate form” to be used ' - 'for the\n' - 'conversion. The alternate form is defined differently for ' - 'different\n' - 'types. This option is only valid for integer, float, ' - 'complex and\n' - 'Decimal types. For integers, when binary, octal, or ' - 'hexadecimal output\n' - 'is used, this option adds the prefix respective "\'0b\'", ' - '"\'0o\'", or\n' - '"\'0x\'" to the output value. For floats, complex and ' - 'Decimal the\n' - 'alternate form causes the result of the conversion to ' - 'always contain a\n' - 'decimal-point character, even if no digits follow it. ' - 'Normally, a\n' - 'decimal-point character appears in the result of these ' - 'conversions\n' - 'only if a digit follows it. In addition, for "\'g\'" and ' - '"\'G\'"\n' - 'conversions, trailing zeros are not removed from the ' - 'result.\n' - '\n' - 'The "\',\'" option signals the use of a comma for a ' - 'thousands separator.\n' - 'For a locale aware separator, use the "\'n\'" integer ' - 'presentation type\n' - 'instead.\n' - '\n' - 'Changed in version 3.1: Added the "\',\'" option (see also ' - '**PEP 378**).\n' - '\n' - 'The "\'_\'" option signals the use of an underscore for a ' - 'thousands\n' - 'separator for floating point presentation types and for ' - 'integer\n' - 'presentation type "\'d\'". For integer presentation types ' - '"\'b\'", "\'o\'",\n' - '"\'x\'", and "\'X\'", underscores will be inserted every 4 ' - 'digits. For\n' - 'other presentation types, specifying this option is an ' - 'error.\n' - '\n' - 'Changed in version 3.6: Added the "\'_\'" option (see also ' - '**PEP 515**).\n' - '\n' - '*width* is a decimal integer defining the minimum field ' - 'width. If not\n' - 'specified, then the field width will be determined by the ' - 'content.\n' - '\n' - 'When no explicit alignment is given, preceding the *width* ' - 'field by a\n' - 'zero ("\'0\'") character enables sign-aware zero-padding ' - 'for numeric\n' - 'types. This is equivalent to a *fill* character of "\'0\'" ' - 'with an\n' - '*alignment* type of "\'=\'".\n' - '\n' - 'The *precision* is a decimal number indicating how many ' - 'digits should\n' - 'be displayed after the decimal point for a floating point ' - 'value\n' - 'formatted with "\'f\'" and "\'F\'", or before and after the ' - 'decimal point\n' - 'for a floating point value formatted with "\'g\'" or ' - '"\'G\'". For non-\n' - 'number types the field indicates the maximum field size - ' - 'in other\n' - 'words, how many characters will be used from the field ' - 'content. The\n' - '*precision* is not allowed for integer values.\n' - '\n' - 'Finally, the *type* determines how the data should be ' - 'presented.\n' - '\n' - 'The available string presentation types are:\n' - '\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | Type | ' - 'Meaning ' - '|\n' - ' ' - '+===========+============================================================+\n' - ' | "\'s\'" | String format. This is the default type ' - 'for strings and |\n' - ' | | may be ' - 'omitted. |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | None | The same as ' - '"\'s\'". |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - '\n' - 'The available integer presentation types are:\n' - '\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | Type | ' - 'Meaning ' - '|\n' - ' ' - '+===========+============================================================+\n' - ' | "\'b\'" | Binary format. Outputs the number in ' - 'base 2. |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | "\'c\'" | Character. Converts the integer to the ' - 'corresponding |\n' - ' | | unicode character before ' - 'printing. |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | "\'d\'" | Decimal Integer. Outputs the number in ' - 'base 10. |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | "\'o\'" | Octal format. Outputs the number in base ' - '8. |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | "\'x\'" | Hex format. Outputs the number in base ' - '16, using lower- |\n' - ' | | case letters for the digits above ' - '9. |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | "\'X\'" | Hex format. Outputs the number in base ' - '16, using upper- |\n' - ' | | case letters for the digits above ' - '9. |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | "\'n\'" | Number. This is the same as "\'d\'", ' - 'except that it uses the |\n' - ' | | current locale setting to insert the ' - 'appropriate number |\n' - ' | | separator ' - 'characters. |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | None | The same as ' - '"\'d\'". |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - '\n' - 'In addition to the above presentation types, integers can ' - 'be formatted\n' - 'with the floating point presentation types listed below ' - '(except "\'n\'"\n' - 'and "None"). When doing so, "float()" is used to convert ' - 'the integer\n' - 'to a floating point number before formatting.\n' - '\n' - 'The available presentation types for floating point and ' - 'decimal values\n' - 'are:\n' - '\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | Type | ' - 'Meaning ' - '|\n' - ' ' - '+===========+============================================================+\n' - ' | "\'e\'" | Exponent notation. Prints the number in ' - 'scientific |\n' - ' | | notation using the letter ‘e’ to indicate ' - 'the exponent. |\n' - ' | | The default precision is ' - '"6". |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | "\'E\'" | Exponent notation. Same as "\'e\'" ' - 'except it uses an upper |\n' - ' | | case ‘E’ as the separator ' - 'character. |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | "\'f\'" | Fixed-point notation. Displays the ' - 'number as a fixed-point |\n' - ' | | number. The default precision is ' - '"6". |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | "\'F\'" | Fixed-point notation. Same as "\'f\'", ' - 'but converts "nan" to |\n' - ' | | "NAN" and "inf" to ' - '"INF". |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | "\'g\'" | General format. For a given precision ' - '"p >= 1", this |\n' - ' | | rounds the number to "p" significant ' - 'digits and then |\n' - ' | | formats the result in either fixed-point ' - 'format or in |\n' - ' | | scientific notation, depending on its ' - 'magnitude. The |\n' - ' | | precise rules are as follows: suppose that ' - 'the result |\n' - ' | | formatted with presentation type "\'e\'" ' - 'and precision "p-1" |\n' - ' | | would have exponent "exp". Then if "-4 <= ' - 'exp < p", the |\n' - ' | | number is formatted with presentation type ' - '"\'f\'" and |\n' - ' | | precision "p-1-exp". Otherwise, the ' - 'number is formatted |\n' - ' | | with presentation type "\'e\'" and ' - 'precision "p-1". In both |\n' - ' | | cases insignificant trailing zeros are ' - 'removed from the |\n' - ' | | significand, and the decimal point is also ' - 'removed if |\n' - ' | | there are no remaining digits following ' - 'it. Positive and |\n' - ' | | negative infinity, positive and negative ' - 'zero, and nans, |\n' - ' | | are formatted as "inf", "-inf", "0", "-0" ' - 'and "nan" |\n' - ' | | respectively, regardless of the ' - 'precision. A precision of |\n' - ' | | "0" is treated as equivalent to a ' - 'precision of "1". The |\n' - ' | | default precision is ' - '"6". |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | "\'G\'" | General format. Same as "\'g\'" except ' - 'switches to "\'E\'" if |\n' - ' | | the number gets too large. The ' - 'representations of infinity |\n' - ' | | and NaN are uppercased, ' - 'too. |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | "\'n\'" | Number. This is the same as "\'g\'", ' - 'except that it uses the |\n' - ' | | current locale setting to insert the ' - 'appropriate number |\n' - ' | | separator ' - 'characters. |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | "\'%\'" | Percentage. Multiplies the number by 100 ' - 'and displays in |\n' - ' | | fixed ("\'f\'") format, followed by a ' - 'percent sign. |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | None | Similar to "\'g\'", except that ' - 'fixed-point notation, when |\n' - ' | | used, has at least one digit past the ' - 'decimal point. The |\n' - ' | | default precision is as high as needed to ' - 'represent the |\n' - ' | | particular value. The overall effect is to ' - 'match the |\n' - ' | | output of "str()" as altered by the other ' - 'format |\n' - ' | | ' - 'modifiers. ' - '|\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - '\n' - '\n' - 'Format examples\n' - '===============\n' - '\n' - 'This section contains examples of the "str.format()" syntax ' - 'and\n' - 'comparison with the old "%"-formatting.\n' - '\n' - 'In most of the cases the syntax is similar to the old ' - '"%"-formatting,\n' - 'with the addition of the "{}" and with ":" used instead of ' - '"%". For\n' - 'example, "\'%03.2f\'" can be translated to "\'{:03.2f}\'".\n' - '\n' - 'The new format syntax also supports new and different ' - 'options, shown\n' - 'in the following examples.\n' - '\n' - 'Accessing arguments by position:\n' - '\n' - " >>> '{0}, {1}, {2}'.format('a', 'b', 'c')\n" - " 'a, b, c'\n" - " >>> '{}, {}, {}'.format('a', 'b', 'c') # 3.1+ only\n" - " 'a, b, c'\n" - " >>> '{2}, {1}, {0}'.format('a', 'b', 'c')\n" - " 'c, b, a'\n" - " >>> '{2}, {1}, {0}'.format(*'abc') # unpacking " - 'argument sequence\n' - " 'c, b, a'\n" - " >>> '{0}{1}{0}'.format('abra', 'cad') # arguments' " - 'indices can be repeated\n' - " 'abracadabra'\n" - '\n' - 'Accessing arguments by name:\n' - '\n' - " >>> 'Coordinates: {latitude}, " - "{longitude}'.format(latitude='37.24N', " - "longitude='-115.81W')\n" - " 'Coordinates: 37.24N, -115.81W'\n" - " >>> coord = {'latitude': '37.24N', 'longitude': " - "'-115.81W'}\n" - " >>> 'Coordinates: {latitude}, " - "{longitude}'.format(**coord)\n" - " 'Coordinates: 37.24N, -115.81W'\n" - '\n' - 'Accessing arguments’ attributes:\n' - '\n' - ' >>> c = 3-5j\n' - " >>> ('The complex number {0} is formed from the real " - "part {0.real} '\n" - " ... 'and the imaginary part {0.imag}.').format(c)\n" - " 'The complex number (3-5j) is formed from the real part " - "3.0 and the imaginary part -5.0.'\n" - ' >>> class Point:\n' - ' ... def __init__(self, x, y):\n' - ' ... self.x, self.y = x, y\n' - ' ... def __str__(self):\n' - " ... return 'Point({self.x}, " - "{self.y})'.format(self=self)\n" - ' ...\n' - ' >>> str(Point(4, 2))\n' - " 'Point(4, 2)'\n" - '\n' - 'Accessing arguments’ items:\n' - '\n' - ' >>> coord = (3, 5)\n' - " >>> 'X: {0[0]}; Y: {0[1]}'.format(coord)\n" - " 'X: 3; Y: 5'\n" - '\n' - 'Replacing "%s" and "%r":\n' - '\n' - ' >>> "repr() shows quotes: {!r}; str() doesn\'t: ' - '{!s}".format(\'test1\', \'test2\')\n' - ' "repr() shows quotes: \'test1\'; str() doesn\'t: test2"\n' - '\n' - 'Aligning the text and specifying a width:\n' - '\n' - " >>> '{:<30}'.format('left aligned')\n" - " 'left aligned '\n" - " >>> '{:>30}'.format('right aligned')\n" - " ' right aligned'\n" - " >>> '{:^30}'.format('centered')\n" - " ' centered '\n" - " >>> '{:*^30}'.format('centered') # use '*' as a fill " - 'char\n' - " '***********centered***********'\n" - '\n' - 'Replacing "%+f", "%-f", and "% f" and specifying a sign:\n' - '\n' - " >>> '{:+f}; {:+f}'.format(3.14, -3.14) # show it " - 'always\n' - " '+3.140000; -3.140000'\n" - " >>> '{: f}; {: f}'.format(3.14, -3.14) # show a space " - 'for positive numbers\n' - " ' 3.140000; -3.140000'\n" - " >>> '{:-f}; {:-f}'.format(3.14, -3.14) # show only the " - "minus -- same as '{:f}; {:f}'\n" - " '3.140000; -3.140000'\n" - '\n' - 'Replacing "%x" and "%o" and converting the value to ' - 'different bases:\n' - '\n' - ' >>> # format also supports binary numbers\n' - ' >>> "int: {0:d}; hex: {0:x}; oct: {0:o}; bin: ' - '{0:b}".format(42)\n' - " 'int: 42; hex: 2a; oct: 52; bin: 101010'\n" - ' >>> # with 0x, 0o, or 0b as prefix:\n' - ' >>> "int: {0:d}; hex: {0:#x}; oct: {0:#o}; bin: ' - '{0:#b}".format(42)\n' - " 'int: 42; hex: 0x2a; oct: 0o52; bin: 0b101010'\n" - '\n' - 'Using the comma as a thousands separator:\n' - '\n' - " >>> '{:,}'.format(1234567890)\n" - " '1,234,567,890'\n" - '\n' - 'Expressing a percentage:\n' - '\n' - ' >>> points = 19\n' - ' >>> total = 22\n' - " >>> 'Correct answers: {:.2%}'.format(points/total)\n" - " 'Correct answers: 86.36%'\n" - '\n' - 'Using type-specific formatting:\n' - '\n' - ' >>> import datetime\n' - ' >>> d = datetime.datetime(2010, 7, 4, 12, 15, 58)\n' - " >>> '{:%Y-%m-%d %H:%M:%S}'.format(d)\n" - " '2010-07-04 12:15:58'\n" - '\n' - 'Nesting arguments and more complex examples:\n' - '\n' - " >>> for align, text in zip('<^>', ['left', 'center', " - "'right']):\n" - " ... '{0:{fill}{align}16}'.format(text, fill=align, " - 'align=align)\n' - ' ...\n' - " 'left<<<<<<<<<<<<'\n" - " '^^^^^center^^^^^'\n" - " '>>>>>>>>>>>right'\n" - ' >>>\n' - ' >>> octets = [192, 168, 0, 1]\n' - " >>> '{:02X}{:02X}{:02X}{:02X}'.format(*octets)\n" - " 'C0A80001'\n" - ' >>> int(_, 16)\n' - ' 3232235521\n' - ' >>>\n' - ' >>> width = 5\n' - ' >>> for num in range(5,12): \n' - " ... for base in 'dXob':\n" - " ... print('{0:{width}{base}}'.format(num, " - "base=base, width=width), end=' ')\n" - ' ... print()\n' - ' ...\n' - ' 5 5 5 101\n' - ' 6 6 6 110\n' - ' 7 7 7 111\n' - ' 8 8 10 1000\n' - ' 9 9 11 1001\n' - ' 10 A 12 1010\n' - ' 11 B 13 1011\n', - 'function': 'Function definitions\n' - '********************\n' - '\n' - 'A function definition defines a user-defined function object ' - '(see\n' - 'section The standard type hierarchy):\n' - '\n' - ' funcdef ::= [decorators] "def" funcname "(" ' - '[parameter_list] ")"\n' - ' ["->" expression] ":" suite\n' - ' decorators ::= decorator+\n' - ' decorator ::= "@" dotted_name ["(" ' - '[argument_list [","]] ")"] NEWLINE\n' - ' dotted_name ::= identifier ("." identifier)*\n' - ' parameter_list ::= defparameter ("," defparameter)* ' - '["," [parameter_list_starargs]]\n' - ' | parameter_list_starargs\n' - ' parameter_list_starargs ::= "*" [parameter] ("," ' - 'defparameter)* ["," ["**" parameter [","]]]\n' - ' | "**" parameter [","]\n' - ' parameter ::= identifier [":" expression]\n' - ' defparameter ::= parameter ["=" expression]\n' - ' funcname ::= identifier\n' - '\n' - 'A function definition is an executable statement. Its execution ' - 'binds\n' - 'the function name in the current local namespace to a function ' - 'object\n' - '(a wrapper around the executable code for the function). This\n' - 'function object contains a reference to the current global ' - 'namespace\n' - 'as the global namespace to be used when the function is called.\n' - '\n' - 'The function definition does not execute the function body; this ' - 'gets\n' - 'executed only when the function is called. [2]\n' - '\n' - 'A function definition may be wrapped by one or more *decorator*\n' - 'expressions. Decorator expressions are evaluated when the ' - 'function is\n' - 'defined, in the scope that contains the function definition. ' - 'The\n' - 'result must be a callable, which is invoked with the function ' - 'object\n' - 'as the only argument. The returned value is bound to the ' - 'function name\n' - 'instead of the function object. Multiple decorators are applied ' - 'in\n' - 'nested fashion. For example, the following code\n' - '\n' - ' @f1(arg)\n' - ' @f2\n' - ' def func(): pass\n' - '\n' - 'is roughly equivalent to\n' - '\n' - ' def func(): pass\n' - ' func = f1(arg)(f2(func))\n' - '\n' - 'except that the original function is not temporarily bound to ' - 'the name\n' - '"func".\n' - '\n' - 'When one or more *parameters* have the form *parameter* "="\n' - '*expression*, the function is said to have “default parameter ' - 'values.”\n' - 'For a parameter with a default value, the corresponding ' - '*argument* may\n' - 'be omitted from a call, in which case the parameter’s default ' - 'value is\n' - 'substituted. If a parameter has a default value, all following\n' - 'parameters up until the “"*"” must also have a default value — ' - 'this is\n' - 'a syntactic restriction that is not expressed by the grammar.\n' - '\n' - '**Default parameter values are evaluated from left to right when ' - 'the\n' - 'function definition is executed.** This means that the ' - 'expression is\n' - 'evaluated once, when the function is defined, and that the same ' - '“pre-\n' - 'computed” value is used for each call. This is especially ' - 'important\n' - 'to understand when a default parameter is a mutable object, such ' - 'as a\n' - 'list or a dictionary: if the function modifies the object (e.g. ' - 'by\n' - 'appending an item to a list), the default value is in effect ' - 'modified.\n' - 'This is generally not what was intended. A way around this is ' - 'to use\n' - '"None" as the default, and explicitly test for it in the body of ' - 'the\n' - 'function, e.g.:\n' - '\n' - ' def whats_on_the_telly(penguin=None):\n' - ' if penguin is None:\n' - ' penguin = []\n' - ' penguin.append("property of the zoo")\n' - ' return penguin\n' - '\n' - 'Function call semantics are described in more detail in section ' - 'Calls.\n' - 'A function call always assigns values to all parameters ' - 'mentioned in\n' - 'the parameter list, either from position arguments, from ' - 'keyword\n' - 'arguments, or from default values. If the form “"*identifier"” ' - 'is\n' - 'present, it is initialized to a tuple receiving any excess ' - 'positional\n' - 'parameters, defaulting to the empty tuple. If the form\n' - '“"**identifier"” is present, it is initialized to a new ordered\n' - 'mapping receiving any excess keyword arguments, defaulting to a ' - 'new\n' - 'empty mapping of the same type. Parameters after “"*"” or\n' - '“"*identifier"” are keyword-only parameters and may only be ' - 'passed\n' - 'used keyword arguments.\n' - '\n' - 'Parameters may have annotations of the form “": expression"” ' - 'following\n' - 'the parameter name. Any parameter may have an annotation even ' - 'those\n' - 'of the form "*identifier" or "**identifier". Functions may ' - 'have\n' - '“return” annotation of the form “"-> expression"” after the ' - 'parameter\n' - 'list. These annotations can be any valid Python expression and ' - 'are\n' - 'evaluated when the function definition is executed. Annotations ' - 'may\n' - 'be evaluated in a different order than they appear in the source ' - 'code.\n' - 'The presence of annotations does not change the semantics of a\n' - 'function. The annotation values are available as values of a\n' - 'dictionary keyed by the parameters’ names in the ' - '"__annotations__"\n' - 'attribute of the function object.\n' - '\n' - 'It is also possible to create anonymous functions (functions not ' - 'bound\n' - 'to a name), for immediate use in expressions. This uses lambda\n' - 'expressions, described in section Lambdas. Note that the ' - 'lambda\n' - 'expression is merely a shorthand for a simplified function ' - 'definition;\n' - 'a function defined in a “"def"” statement can be passed around ' - 'or\n' - 'assigned to another name just like a function defined by a ' - 'lambda\n' - 'expression. The “"def"” form is actually more powerful since ' - 'it\n' - 'allows the execution of multiple statements and annotations.\n' - '\n' - '**Programmer’s note:** Functions are first-class objects. A ' - '“"def"”\n' - 'statement executed inside a function definition defines a local\n' - 'function that can be returned or passed around. Free variables ' - 'used\n' - 'in the nested function can access the local variables of the ' - 'function\n' - 'containing the def. See section Naming and binding for ' - 'details.\n' - '\n' - 'See also:\n' - '\n' - ' **PEP 3107** - Function Annotations\n' - ' The original specification for function annotations.\n', - 'global': 'The "global" statement\n' - '**********************\n' - '\n' - ' global_stmt ::= "global" identifier ("," identifier)*\n' - '\n' - 'The "global" statement is a declaration which holds for the ' - 'entire\n' - 'current code block. It means that the listed identifiers are to ' - 'be\n' - 'interpreted as globals. It would be impossible to assign to a ' - 'global\n' - 'variable without "global", although free variables may refer to\n' - 'globals without being declared global.\n' - '\n' - 'Names listed in a "global" statement must not be used in the same ' - 'code\n' - 'block textually preceding that "global" statement.\n' - '\n' - 'Names listed in a "global" statement must not be defined as ' - 'formal\n' - 'parameters or in a "for" loop control target, "class" definition,\n' - 'function definition, "import" statement, or variable annotation.\n' - '\n' - '**CPython implementation detail:** The current implementation does ' - 'not\n' - 'enforce some of these restrictions, but programs should not abuse ' - 'this\n' - 'freedom, as future implementations may enforce them or silently ' - 'change\n' - 'the meaning of the program.\n' - '\n' - '**Programmer’s note:** "global" is a directive to the parser. It\n' - 'applies only to code parsed at the same time as the "global"\n' - 'statement. In particular, a "global" statement contained in a ' - 'string\n' - 'or code object supplied to the built-in "exec()" function does ' - 'not\n' - 'affect the code block *containing* the function call, and code\n' - 'contained in such a string is unaffected by "global" statements in ' - 'the\n' - 'code containing the function call. The same applies to the ' - '"eval()"\n' - 'and "compile()" functions.\n', - 'id-classes': 'Reserved classes of identifiers\n' - '*******************************\n' - '\n' - 'Certain classes of identifiers (besides keywords) have ' - 'special\n' - 'meanings. These classes are identified by the patterns of ' - 'leading and\n' - 'trailing underscore characters:\n' - '\n' - '"_*"\n' - ' Not imported by "from module import *". The special ' - 'identifier "_"\n' - ' is used in the interactive interpreter to store the result ' - 'of the\n' - ' last evaluation; it is stored in the "builtins" module. ' - 'When not\n' - ' in interactive mode, "_" has no special meaning and is not ' - 'defined.\n' - ' See section The import statement.\n' - '\n' - ' Note: The name "_" is often used in conjunction with\n' - ' internationalization; refer to the documentation for the\n' - ' "gettext" module for more information on this ' - 'convention.\n' - '\n' - '"__*__"\n' - ' System-defined names. These names are defined by the ' - 'interpreter\n' - ' and its implementation (including the standard library). ' - 'Current\n' - ' system names are discussed in the Special method names ' - 'section and\n' - ' elsewhere. More will likely be defined in future versions ' - 'of\n' - ' Python. *Any* use of "__*__" names, in any context, that ' - 'does not\n' - ' follow explicitly documented use, is subject to breakage ' - 'without\n' - ' warning.\n' - '\n' - '"__*"\n' - ' Class-private names. Names in this category, when used ' - 'within the\n' - ' context of a class definition, are re-written to use a ' - 'mangled form\n' - ' to help avoid name clashes between “private” attributes of ' - 'base and\n' - ' derived classes. See section Identifiers (Names).\n', - 'identifiers': 'Identifiers and keywords\n' - '************************\n' - '\n' - 'Identifiers (also referred to as *names*) are described by ' - 'the\n' - 'following lexical definitions.\n' - '\n' - 'The syntax of identifiers in Python is based on the Unicode ' - 'standard\n' - 'annex UAX-31, with elaboration and changes as defined below; ' - 'see also\n' - '**PEP 3131** for further details.\n' - '\n' - 'Within the ASCII range (U+0001..U+007F), the valid characters ' - 'for\n' - 'identifiers are the same as in Python 2.x: the uppercase and ' - 'lowercase\n' - 'letters "A" through "Z", the underscore "_" and, except for ' - 'the first\n' - 'character, the digits "0" through "9".\n' - '\n' - 'Python 3.0 introduces additional characters from outside the ' - 'ASCII\n' - 'range (see **PEP 3131**). For these characters, the ' - 'classification\n' - 'uses the version of the Unicode Character Database as ' - 'included in the\n' - '"unicodedata" module.\n' - '\n' - 'Identifiers are unlimited in length. Case is significant.\n' - '\n' - ' identifier ::= xid_start xid_continue*\n' - ' id_start ::= \n' - ' id_continue ::= \n' - ' xid_start ::= \n' - ' xid_continue ::= \n' - '\n' - 'The Unicode category codes mentioned above stand for:\n' - '\n' - '* *Lu* - uppercase letters\n' - '\n' - '* *Ll* - lowercase letters\n' - '\n' - '* *Lt* - titlecase letters\n' - '\n' - '* *Lm* - modifier letters\n' - '\n' - '* *Lo* - other letters\n' - '\n' - '* *Nl* - letter numbers\n' - '\n' - '* *Mn* - nonspacing marks\n' - '\n' - '* *Mc* - spacing combining marks\n' - '\n' - '* *Nd* - decimal numbers\n' - '\n' - '* *Pc* - connector punctuations\n' - '\n' - '* *Other_ID_Start* - explicit list of characters in ' - 'PropList.txt to\n' - ' support backwards compatibility\n' - '\n' - '* *Other_ID_Continue* - likewise\n' - '\n' - 'All identifiers are converted into the normal form NFKC while ' - 'parsing;\n' - 'comparison of identifiers is based on NFKC.\n' - '\n' - 'A non-normative HTML file listing all valid identifier ' - 'characters for\n' - 'Unicode 4.1 can be found at https://www.dcl.hpi.uni-\n' - 'potsdam.de/home/loewis/table-3131.html.\n' - '\n' - '\n' - 'Keywords\n' - '========\n' - '\n' - 'The following identifiers are used as reserved words, or ' - '*keywords* of\n' - 'the language, and cannot be used as ordinary identifiers. ' - 'They must\n' - 'be spelled exactly as written here:\n' - '\n' - ' False class finally is return\n' - ' None continue for lambda try\n' - ' True def from nonlocal while\n' - ' and del global not with\n' - ' as elif if or yield\n' - ' assert else import pass\n' - ' break except in raise\n' - '\n' - '\n' - 'Reserved classes of identifiers\n' - '===============================\n' - '\n' - 'Certain classes of identifiers (besides keywords) have ' - 'special\n' - 'meanings. These classes are identified by the patterns of ' - 'leading and\n' - 'trailing underscore characters:\n' - '\n' - '"_*"\n' - ' Not imported by "from module import *". The special ' - 'identifier "_"\n' - ' is used in the interactive interpreter to store the result ' - 'of the\n' - ' last evaluation; it is stored in the "builtins" module. ' - 'When not\n' - ' in interactive mode, "_" has no special meaning and is not ' - 'defined.\n' - ' See section The import statement.\n' - '\n' - ' Note: The name "_" is often used in conjunction with\n' - ' internationalization; refer to the documentation for ' - 'the\n' - ' "gettext" module for more information on this ' - 'convention.\n' - '\n' - '"__*__"\n' - ' System-defined names. These names are defined by the ' - 'interpreter\n' - ' and its implementation (including the standard library). ' - 'Current\n' - ' system names are discussed in the Special method names ' - 'section and\n' - ' elsewhere. More will likely be defined in future versions ' - 'of\n' - ' Python. *Any* use of "__*__" names, in any context, that ' - 'does not\n' - ' follow explicitly documented use, is subject to breakage ' - 'without\n' - ' warning.\n' - '\n' - '"__*"\n' - ' Class-private names. Names in this category, when used ' - 'within the\n' - ' context of a class definition, are re-written to use a ' - 'mangled form\n' - ' to help avoid name clashes between “private” attributes of ' - 'base and\n' - ' derived classes. See section Identifiers (Names).\n', - 'if': 'The "if" statement\n' - '******************\n' - '\n' - 'The "if" statement is used for conditional execution:\n' - '\n' - ' if_stmt ::= "if" expression ":" suite\n' - ' ("elif" expression ":" suite)*\n' - ' ["else" ":" suite]\n' - '\n' - 'It selects exactly one of the suites by evaluating the expressions ' - 'one\n' - 'by one until one is found to be true (see section Boolean operations\n' - 'for the definition of true and false); then that suite is executed\n' - '(and no other part of the "if" statement is executed or evaluated).\n' - 'If all expressions are false, the suite of the "else" clause, if\n' - 'present, is executed.\n', - 'imaginary': 'Imaginary literals\n' - '******************\n' - '\n' - 'Imaginary literals are described by the following lexical ' - 'definitions:\n' - '\n' - ' imagnumber ::= (floatnumber | digitpart) ("j" | "J")\n' - '\n' - 'An imaginary literal yields a complex number with a real part ' - 'of 0.0.\n' - 'Complex numbers are represented as a pair of floating point ' - 'numbers\n' - 'and have the same restrictions on their range. To create a ' - 'complex\n' - 'number with a nonzero real part, add a floating point number to ' - 'it,\n' - 'e.g., "(3+4j)". Some examples of imaginary literals:\n' - '\n' - ' 3.14j 10.j 10j .001j 1e100j 3.14e-10j ' - '3.14_15_93j\n', - 'import': 'The "import" statement\n' - '**********************\n' - '\n' - ' import_stmt ::= "import" module ["as" identifier] ("," ' - 'module ["as" identifier])*\n' - ' | "from" relative_module "import" identifier ' - '["as" identifier]\n' - ' ("," identifier ["as" identifier])*\n' - ' | "from" relative_module "import" "(" ' - 'identifier ["as" identifier]\n' - ' ("," identifier ["as" identifier])* [","] ")"\n' - ' | "from" module "import" "*"\n' - ' module ::= (identifier ".")* identifier\n' - ' relative_module ::= "."* module | "."+\n' - '\n' - 'The basic import statement (no "from" clause) is executed in two\n' - 'steps:\n' - '\n' - '1. find a module, loading and initializing it if necessary\n' - '\n' - '2. define a name or names in the local namespace for the scope\n' - ' where the "import" statement occurs.\n' - '\n' - 'When the statement contains multiple clauses (separated by commas) ' - 'the\n' - 'two steps are carried out separately for each clause, just as ' - 'though\n' - 'the clauses had been separated out into individual import ' - 'statements.\n' - '\n' - 'The details of the first step, finding and loading modules are\n' - 'described in greater detail in the section on the import system, ' - 'which\n' - 'also describes the various types of packages and modules that can ' - 'be\n' - 'imported, as well as all the hooks that can be used to customize ' - 'the\n' - 'import system. Note that failures in this step may indicate ' - 'either\n' - 'that the module could not be located, *or* that an error occurred\n' - 'while initializing the module, which includes execution of the\n' - 'module’s code.\n' - '\n' - 'If the requested module is retrieved successfully, it will be ' - 'made\n' - 'available in the local namespace in one of three ways:\n' - '\n' - '* If the module name is followed by "as", then the name following\n' - ' "as" is bound directly to the imported module.\n' - '\n' - '* If no other name is specified, and the module being imported is ' - 'a\n' - ' top level module, the module’s name is bound in the local ' - 'namespace\n' - ' as a reference to the imported module\n' - '\n' - '* If the module being imported is *not* a top level module, then ' - 'the\n' - ' name of the top level package that contains the module is bound ' - 'in\n' - ' the local namespace as a reference to the top level package. ' - 'The\n' - ' imported module must be accessed using its full qualified name\n' - ' rather than directly\n' - '\n' - 'The "from" form uses a slightly more complex process:\n' - '\n' - '1. find the module specified in the "from" clause, loading and\n' - ' initializing it if necessary;\n' - '\n' - '2. for each of the identifiers specified in the "import" clauses:\n' - '\n' - ' 1. check if the imported module has an attribute by that name\n' - '\n' - ' 2. if not, attempt to import a submodule with that name and ' - 'then\n' - ' check the imported module again for that attribute\n' - '\n' - ' 3. if the attribute is not found, "ImportError" is raised.\n' - '\n' - ' 4. otherwise, a reference to that value is stored in the local\n' - ' namespace, using the name in the "as" clause if it is ' - 'present,\n' - ' otherwise using the attribute name\n' - '\n' - 'Examples:\n' - '\n' - ' import foo # foo imported and bound locally\n' - ' import foo.bar.baz # foo.bar.baz imported, foo bound ' - 'locally\n' - ' import foo.bar.baz as fbb # foo.bar.baz imported and bound as ' - 'fbb\n' - ' from foo.bar import baz # foo.bar.baz imported and bound as ' - 'baz\n' - ' from foo import attr # foo imported and foo.attr bound as ' - 'attr\n' - '\n' - 'If the list of identifiers is replaced by a star ("\'*\'"), all ' - 'public\n' - 'names defined in the module are bound in the local namespace for ' - 'the\n' - 'scope where the "import" statement occurs.\n' - '\n' - 'The *public names* defined by a module are determined by checking ' - 'the\n' - 'module’s namespace for a variable named "__all__"; if defined, it ' - 'must\n' - 'be a sequence of strings which are names defined or imported by ' - 'that\n' - 'module. The names given in "__all__" are all considered public ' - 'and\n' - 'are required to exist. If "__all__" is not defined, the set of ' - 'public\n' - 'names includes all names found in the module’s namespace which do ' - 'not\n' - 'begin with an underscore character ("\'_\'"). "__all__" should ' - 'contain\n' - 'the entire public API. It is intended to avoid accidentally ' - 'exporting\n' - 'items that are not part of the API (such as library modules which ' - 'were\n' - 'imported and used within the module).\n' - '\n' - 'The wild card form of import — "from module import *" — is only\n' - 'allowed at the module level. Attempting to use it in class or\n' - 'function definitions will raise a "SyntaxError".\n' - '\n' - 'When specifying what module to import you do not have to specify ' - 'the\n' - 'absolute name of the module. When a module or package is ' - 'contained\n' - 'within another package it is possible to make a relative import ' - 'within\n' - 'the same top package without having to mention the package name. ' - 'By\n' - 'using leading dots in the specified module or package after "from" ' - 'you\n' - 'can specify how high to traverse up the current package hierarchy\n' - 'without specifying exact names. One leading dot means the current\n' - 'package where the module making the import exists. Two dots means ' - 'up\n' - 'one package level. Three dots is up two levels, etc. So if you ' - 'execute\n' - '"from . import mod" from a module in the "pkg" package then you ' - 'will\n' - 'end up importing "pkg.mod". If you execute "from ..subpkg2 import ' - 'mod"\n' - 'from within "pkg.subpkg1" you will import "pkg.subpkg2.mod". The\n' - 'specification for relative imports is contained within **PEP ' - '328**.\n' - '\n' - '"importlib.import_module()" is provided to support applications ' - 'that\n' - 'determine dynamically the modules to be loaded.\n' - '\n' - '\n' - 'Future statements\n' - '=================\n' - '\n' - 'A *future statement* is a directive to the compiler that a ' - 'particular\n' - 'module should be compiled using syntax or semantics that will be\n' - 'available in a specified future release of Python where the ' - 'feature\n' - 'becomes standard.\n' - '\n' - 'The future statement is intended to ease migration to future ' - 'versions\n' - 'of Python that introduce incompatible changes to the language. ' - 'It\n' - 'allows use of the new features on a per-module basis before the\n' - 'release in which the feature becomes standard.\n' - '\n' - ' future_stmt ::= "from" "__future__" "import" feature ["as" ' - 'identifier]\n' - ' ("," feature ["as" identifier])*\n' - ' | "from" "__future__" "import" "(" feature ' - '["as" identifier]\n' - ' ("," feature ["as" identifier])* [","] ")"\n' - ' feature ::= identifier\n' - '\n' - 'A future statement must appear near the top of the module. The ' - 'only\n' - 'lines that can appear before a future statement are:\n' - '\n' - '* the module docstring (if any),\n' - '\n' - '* comments,\n' - '\n' - '* blank lines, and\n' - '\n' - '* other future statements.\n' - '\n' - 'The features recognized by Python 3.0 are "absolute_import",\n' - '"division", "generators", "unicode_literals", "print_function",\n' - '"nested_scopes" and "with_statement". They are all redundant ' - 'because\n' - 'they are always enabled, and only kept for backwards ' - 'compatibility.\n' - '\n' - 'A future statement is recognized and treated specially at compile\n' - 'time: Changes to the semantics of core constructs are often\n' - 'implemented by generating different code. It may even be the ' - 'case\n' - 'that a new feature introduces new incompatible syntax (such as a ' - 'new\n' - 'reserved word), in which case the compiler may need to parse the\n' - 'module differently. Such decisions cannot be pushed off until\n' - 'runtime.\n' - '\n' - 'For any given release, the compiler knows which feature names ' - 'have\n' - 'been defined, and raises a compile-time error if a future ' - 'statement\n' - 'contains a feature not known to it.\n' - '\n' - 'The direct runtime semantics are the same as for any import ' - 'statement:\n' - 'there is a standard module "__future__", described later, and it ' - 'will\n' - 'be imported in the usual way at the time the future statement is\n' - 'executed.\n' - '\n' - 'The interesting runtime semantics depend on the specific feature\n' - 'enabled by the future statement.\n' - '\n' - 'Note that there is nothing special about the statement:\n' - '\n' - ' import __future__ [as name]\n' - '\n' - 'That is not a future statement; it’s an ordinary import statement ' - 'with\n' - 'no special semantics or syntax restrictions.\n' - '\n' - 'Code compiled by calls to the built-in functions "exec()" and\n' - '"compile()" that occur in a module "M" containing a future ' - 'statement\n' - 'will, by default, use the new syntax or semantics associated with ' - 'the\n' - 'future statement. This can be controlled by optional arguments ' - 'to\n' - '"compile()" — see the documentation of that function for details.\n' - '\n' - 'A future statement typed at an interactive interpreter prompt ' - 'will\n' - 'take effect for the rest of the interpreter session. If an\n' - 'interpreter is started with the "-i" option, is passed a script ' - 'name\n' - 'to execute, and the script includes a future statement, it will be ' - 'in\n' - 'effect in the interactive session started after the script is\n' - 'executed.\n' - '\n' - 'See also:\n' - '\n' - ' **PEP 236** - Back to the __future__\n' - ' The original proposal for the __future__ mechanism.\n', - 'in': 'Membership test operations\n' - '**************************\n' - '\n' - 'The operators "in" and "not in" test for membership. "x in s"\n' - 'evaluates to "True" if *x* is a member of *s*, and "False" otherwise.\n' - '"x not in s" returns the negation of "x in s". All built-in ' - 'sequences\n' - 'and set types support this as well as dictionary, for which "in" ' - 'tests\n' - 'whether the dictionary has a given key. For container types such as\n' - 'list, tuple, set, frozenset, dict, or collections.deque, the\n' - 'expression "x in y" is equivalent to "any(x is e or x == e for e in\n' - 'y)".\n' - '\n' - 'For the string and bytes types, "x in y" is "True" if and only if *x*\n' - 'is a substring of *y*. An equivalent test is "y.find(x) != -1".\n' - 'Empty strings are always considered to be a substring of any other\n' - 'string, so """ in "abc"" will return "True".\n' - '\n' - 'For user-defined classes which define the "__contains__()" method, "x\n' - 'in y" returns "True" if "y.__contains__(x)" returns a true value, and\n' - '"False" otherwise.\n' - '\n' - 'For user-defined classes which do not define "__contains__()" but do\n' - 'define "__iter__()", "x in y" is "True" if some value "z" with "x ==\n' - 'z" is produced while iterating over "y". If an exception is raised\n' - 'during the iteration, it is as if "in" raised that exception.\n' - '\n' - 'Lastly, the old-style iteration protocol is tried: if a class defines\n' - '"__getitem__()", "x in y" is "True" if and only if there is a non-\n' - 'negative integer index *i* such that "x == y[i]", and all lower\n' - 'integer indices do not raise "IndexError" exception. (If any other\n' - 'exception is raised, it is as if "in" raised that exception).\n' - '\n' - 'The operator "not in" is defined to have the inverse true value of\n' - '"in".\n', - 'integers': 'Integer literals\n' - '****************\n' - '\n' - 'Integer literals are described by the following lexical ' - 'definitions:\n' - '\n' - ' integer ::= decinteger | bininteger | octinteger | ' - 'hexinteger\n' - ' decinteger ::= nonzerodigit (["_"] digit)* | "0"+ (["_"] ' - '"0")*\n' - ' bininteger ::= "0" ("b" | "B") (["_"] bindigit)+\n' - ' octinteger ::= "0" ("o" | "O") (["_"] octdigit)+\n' - ' hexinteger ::= "0" ("x" | "X") (["_"] hexdigit)+\n' - ' nonzerodigit ::= "1"..."9"\n' - ' digit ::= "0"..."9"\n' - ' bindigit ::= "0" | "1"\n' - ' octdigit ::= "0"..."7"\n' - ' hexdigit ::= digit | "a"..."f" | "A"..."F"\n' - '\n' - 'There is no limit for the length of integer literals apart from ' - 'what\n' - 'can be stored in available memory.\n' - '\n' - 'Underscores are ignored for determining the numeric value of ' - 'the\n' - 'literal. They can be used to group digits for enhanced ' - 'readability.\n' - 'One underscore can occur between digits, and after base ' - 'specifiers\n' - 'like "0x".\n' - '\n' - 'Note that leading zeros in a non-zero decimal number are not ' - 'allowed.\n' - 'This is for disambiguation with C-style octal literals, which ' - 'Python\n' - 'used before version 3.0.\n' - '\n' - 'Some examples of integer literals:\n' - '\n' - ' 7 2147483647 0o177 0b100110111\n' - ' 3 79228162514264337593543950336 0o377 0xdeadbeef\n' - ' 100_000_000_000 0b_1110_0101\n' - '\n' - 'Changed in version 3.6: Underscores are now allowed for ' - 'grouping\n' - 'purposes in literals.\n', - 'lambda': 'Lambdas\n' - '*******\n' - '\n' - ' lambda_expr ::= "lambda" [parameter_list] ":" ' - 'expression\n' - ' lambda_expr_nocond ::= "lambda" [parameter_list] ":" ' - 'expression_nocond\n' - '\n' - 'Lambda expressions (sometimes called lambda forms) are used to ' - 'create\n' - 'anonymous functions. The expression "lambda parameters: ' - 'expression"\n' - 'yields a function object. The unnamed object behaves like a ' - 'function\n' - 'object defined with:\n' - '\n' - ' def (parameters):\n' - ' return expression\n' - '\n' - 'See section Function definitions for the syntax of parameter ' - 'lists.\n' - 'Note that functions created with lambda expressions cannot ' - 'contain\n' - 'statements or annotations.\n', - 'lists': 'List displays\n' - '*************\n' - '\n' - 'A list display is a possibly empty series of expressions enclosed ' - 'in\n' - 'square brackets:\n' - '\n' - ' list_display ::= "[" [starred_list | comprehension] "]"\n' - '\n' - 'A list display yields a new list object, the contents being ' - 'specified\n' - 'by either a list of expressions or a comprehension. When a comma-\n' - 'separated list of expressions is supplied, its elements are ' - 'evaluated\n' - 'from left to right and placed into the list object in that order.\n' - 'When a comprehension is supplied, the list is constructed from the\n' - 'elements resulting from the comprehension.\n', - 'naming': 'Naming and binding\n' - '******************\n' - '\n' - '\n' - 'Binding of names\n' - '================\n' - '\n' - '*Names* refer to objects. Names are introduced by name binding\n' - 'operations.\n' - '\n' - 'The following constructs bind names: formal parameters to ' - 'functions,\n' - '"import" statements, class and function definitions (these bind ' - 'the\n' - 'class or function name in the defining block), and targets that ' - 'are\n' - 'identifiers if occurring in an assignment, "for" loop header, or ' - 'after\n' - '"as" in a "with" statement or "except" clause. The "import" ' - 'statement\n' - 'of the form "from ... import *" binds all names defined in the\n' - 'imported module, except those beginning with an underscore. This ' - 'form\n' - 'may only be used at the module level.\n' - '\n' - 'A target occurring in a "del" statement is also considered bound ' - 'for\n' - 'this purpose (though the actual semantics are to unbind the ' - 'name).\n' - '\n' - 'Each assignment or import statement occurs within a block defined ' - 'by a\n' - 'class or function definition or at the module level (the ' - 'top-level\n' - 'code block).\n' - '\n' - 'If a name is bound in a block, it is a local variable of that ' - 'block,\n' - 'unless declared as "nonlocal" or "global". If a name is bound at ' - 'the\n' - 'module level, it is a global variable. (The variables of the ' - 'module\n' - 'code block are local and global.) If a variable is used in a ' - 'code\n' - 'block but not defined there, it is a *free variable*.\n' - '\n' - 'Each occurrence of a name in the program text refers to the ' - '*binding*\n' - 'of that name established by the following name resolution rules.\n' - '\n' - '\n' - 'Resolution of names\n' - '===================\n' - '\n' - 'A *scope* defines the visibility of a name within a block. If a ' - 'local\n' - 'variable is defined in a block, its scope includes that block. If ' - 'the\n' - 'definition occurs in a function block, the scope extends to any ' - 'blocks\n' - 'contained within the defining one, unless a contained block ' - 'introduces\n' - 'a different binding for the name.\n' - '\n' - 'When a name is used in a code block, it is resolved using the ' - 'nearest\n' - 'enclosing scope. The set of all such scopes visible to a code ' - 'block\n' - 'is called the block’s *environment*.\n' - '\n' - 'When a name is not found at all, a "NameError" exception is ' - 'raised. If\n' - 'the current scope is a function scope, and the name refers to a ' - 'local\n' - 'variable that has not yet been bound to a value at the point where ' - 'the\n' - 'name is used, an "UnboundLocalError" exception is raised.\n' - '"UnboundLocalError" is a subclass of "NameError".\n' - '\n' - 'If a name binding operation occurs anywhere within a code block, ' - 'all\n' - 'uses of the name within the block are treated as references to ' - 'the\n' - 'current block. This can lead to errors when a name is used within ' - 'a\n' - 'block before it is bound. This rule is subtle. Python lacks\n' - 'declarations and allows name binding operations to occur anywhere\n' - 'within a code block. The local variables of a code block can be\n' - 'determined by scanning the entire text of the block for name ' - 'binding\n' - 'operations.\n' - '\n' - 'If the "global" statement occurs within a block, all uses of the ' - 'name\n' - 'specified in the statement refer to the binding of that name in ' - 'the\n' - 'top-level namespace. Names are resolved in the top-level ' - 'namespace by\n' - 'searching the global namespace, i.e. the namespace of the module\n' - 'containing the code block, and the builtins namespace, the ' - 'namespace\n' - 'of the module "builtins". The global namespace is searched ' - 'first. If\n' - 'the name is not found there, the builtins namespace is searched. ' - 'The\n' - '"global" statement must precede all uses of the name.\n' - '\n' - 'The "global" statement has the same scope as a name binding ' - 'operation\n' - 'in the same block. If the nearest enclosing scope for a free ' - 'variable\n' - 'contains a global statement, the free variable is treated as a ' - 'global.\n' - '\n' - 'The "nonlocal" statement causes corresponding names to refer to\n' - 'previously bound variables in the nearest enclosing function ' - 'scope.\n' - '"SyntaxError" is raised at compile time if the given name does ' - 'not\n' - 'exist in any enclosing function scope.\n' - '\n' - 'The namespace for a module is automatically created the first time ' - 'a\n' - 'module is imported. The main module for a script is always ' - 'called\n' - '"__main__".\n' - '\n' - 'Class definition blocks and arguments to "exec()" and "eval()" ' - 'are\n' - 'special in the context of name resolution. A class definition is ' - 'an\n' - 'executable statement that may use and define names. These ' - 'references\n' - 'follow the normal rules for name resolution with an exception ' - 'that\n' - 'unbound local variables are looked up in the global namespace. ' - 'The\n' - 'namespace of the class definition becomes the attribute dictionary ' - 'of\n' - 'the class. The scope of names defined in a class block is limited ' - 'to\n' - 'the class block; it does not extend to the code blocks of methods ' - '–\n' - 'this includes comprehensions and generator expressions since they ' - 'are\n' - 'implemented using a function scope. This means that the ' - 'following\n' - 'will fail:\n' - '\n' - ' class A:\n' - ' a = 42\n' - ' b = list(a + i for i in range(10))\n' - '\n' - '\n' - 'Builtins and restricted execution\n' - '=================================\n' - '\n' - '**CPython implementation detail:** Users should not touch\n' - '"__builtins__"; it is strictly an implementation detail. Users\n' - 'wanting to override values in the builtins namespace should ' - '"import"\n' - 'the "builtins" module and modify its attributes appropriately.\n' - '\n' - 'The builtins namespace associated with the execution of a code ' - 'block\n' - 'is actually found by looking up the name "__builtins__" in its ' - 'global\n' - 'namespace; this should be a dictionary or a module (in the latter ' - 'case\n' - 'the module’s dictionary is used). By default, when in the ' - '"__main__"\n' - 'module, "__builtins__" is the built-in module "builtins"; when in ' - 'any\n' - 'other module, "__builtins__" is an alias for the dictionary of ' - 'the\n' - '"builtins" module itself.\n' - '\n' - '\n' - 'Interaction with dynamic features\n' - '=================================\n' - '\n' - 'Name resolution of free variables occurs at runtime, not at ' - 'compile\n' - 'time. This means that the following code will print 42:\n' - '\n' - ' i = 10\n' - ' def f():\n' - ' print(i)\n' - ' i = 42\n' - ' f()\n' - '\n' - 'The "eval()" and "exec()" functions do not have access to the ' - 'full\n' - 'environment for resolving names. Names may be resolved in the ' - 'local\n' - 'and global namespaces of the caller. Free variables are not ' - 'resolved\n' - 'in the nearest enclosing namespace, but in the global namespace. ' - '[1]\n' - 'The "exec()" and "eval()" functions have optional arguments to\n' - 'override the global and local namespace. If only one namespace ' - 'is\n' - 'specified, it is used for both.\n', - 'nonlocal': 'The "nonlocal" statement\n' - '************************\n' - '\n' - ' nonlocal_stmt ::= "nonlocal" identifier ("," identifier)*\n' - '\n' - 'The "nonlocal" statement causes the listed identifiers to refer ' - 'to\n' - 'previously bound variables in the nearest enclosing scope ' - 'excluding\n' - 'globals. This is important because the default behavior for ' - 'binding is\n' - 'to search the local namespace first. The statement allows\n' - 'encapsulated code to rebind variables outside of the local ' - 'scope\n' - 'besides the global (module) scope.\n' - '\n' - 'Names listed in a "nonlocal" statement, unlike those listed in ' - 'a\n' - '"global" statement, must refer to pre-existing bindings in an\n' - 'enclosing scope (the scope in which a new binding should be ' - 'created\n' - 'cannot be determined unambiguously).\n' - '\n' - 'Names listed in a "nonlocal" statement must not collide with ' - 'pre-\n' - 'existing bindings in the local scope.\n' - '\n' - 'See also:\n' - '\n' - ' **PEP 3104** - Access to Names in Outer Scopes\n' - ' The specification for the "nonlocal" statement.\n', - 'numbers': 'Numeric literals\n' - '****************\n' - '\n' - 'There are three types of numeric literals: integers, floating ' - 'point\n' - 'numbers, and imaginary numbers. There are no complex literals\n' - '(complex numbers can be formed by adding a real number and an\n' - 'imaginary number).\n' - '\n' - 'Note that numeric literals do not include a sign; a phrase like ' - '"-1"\n' - 'is actually an expression composed of the unary operator ‘"-"‘ ' - 'and the\n' - 'literal "1".\n', - 'numeric-types': 'Emulating numeric types\n' - '***********************\n' - '\n' - 'The following methods can be defined to emulate numeric ' - 'objects.\n' - 'Methods corresponding to operations that are not supported ' - 'by the\n' - 'particular kind of number implemented (e.g., bitwise ' - 'operations for\n' - 'non-integral numbers) should be left undefined.\n' - '\n' - 'object.__add__(self, other)\n' - 'object.__sub__(self, other)\n' - 'object.__mul__(self, other)\n' - 'object.__matmul__(self, other)\n' - 'object.__truediv__(self, other)\n' - 'object.__floordiv__(self, other)\n' - 'object.__mod__(self, other)\n' - 'object.__divmod__(self, other)\n' - 'object.__pow__(self, other[, modulo])\n' - 'object.__lshift__(self, other)\n' - 'object.__rshift__(self, other)\n' - 'object.__and__(self, other)\n' - 'object.__xor__(self, other)\n' - 'object.__or__(self, other)\n' - '\n' - ' These methods are called to implement the binary ' - 'arithmetic\n' - ' operations ("+", "-", "*", "@", "/", "//", "%", ' - '"divmod()",\n' - ' "pow()", "**", "<<", ">>", "&", "^", "|"). For ' - 'instance, to\n' - ' evaluate the expression "x + y", where *x* is an ' - 'instance of a\n' - ' class that has an "__add__()" method, "x.__add__(y)" is ' - 'called.\n' - ' The "__divmod__()" method should be the equivalent to ' - 'using\n' - ' "__floordiv__()" and "__mod__()"; it should not be ' - 'related to\n' - ' "__truediv__()". Note that "__pow__()" should be ' - 'defined to accept\n' - ' an optional third argument if the ternary version of the ' - 'built-in\n' - ' "pow()" function is to be supported.\n' - '\n' - ' If one of those methods does not support the operation ' - 'with the\n' - ' supplied arguments, it should return "NotImplemented".\n' - '\n' - 'object.__radd__(self, other)\n' - 'object.__rsub__(self, other)\n' - 'object.__rmul__(self, other)\n' - 'object.__rmatmul__(self, other)\n' - 'object.__rtruediv__(self, other)\n' - 'object.__rfloordiv__(self, other)\n' - 'object.__rmod__(self, other)\n' - 'object.__rdivmod__(self, other)\n' - 'object.__rpow__(self, other)\n' - 'object.__rlshift__(self, other)\n' - 'object.__rrshift__(self, other)\n' - 'object.__rand__(self, other)\n' - 'object.__rxor__(self, other)\n' - 'object.__ror__(self, other)\n' - '\n' - ' These methods are called to implement the binary ' - 'arithmetic\n' - ' operations ("+", "-", "*", "@", "/", "//", "%", ' - '"divmod()",\n' - ' "pow()", "**", "<<", ">>", "&", "^", "|") with reflected ' - '(swapped)\n' - ' operands. These functions are only called if the left ' - 'operand does\n' - ' not support the corresponding operation [3] and the ' - 'operands are of\n' - ' different types. [4] For instance, to evaluate the ' - 'expression "x -\n' - ' y", where *y* is an instance of a class that has an ' - '"__rsub__()"\n' - ' method, "y.__rsub__(x)" is called if "x.__sub__(y)" ' - 'returns\n' - ' *NotImplemented*.\n' - '\n' - ' Note that ternary "pow()" will not try calling ' - '"__rpow__()" (the\n' - ' coercion rules would become too complicated).\n' - '\n' - ' Note: If the right operand’s type is a subclass of the ' - 'left\n' - ' operand’s type and that subclass provides the ' - 'reflected method\n' - ' for the operation, this method will be called before ' - 'the left\n' - ' operand’s non-reflected method. This behavior allows ' - 'subclasses\n' - ' to override their ancestors’ operations.\n' - '\n' - 'object.__iadd__(self, other)\n' - 'object.__isub__(self, other)\n' - 'object.__imul__(self, other)\n' - 'object.__imatmul__(self, other)\n' - 'object.__itruediv__(self, other)\n' - 'object.__ifloordiv__(self, other)\n' - 'object.__imod__(self, other)\n' - 'object.__ipow__(self, other[, modulo])\n' - 'object.__ilshift__(self, other)\n' - 'object.__irshift__(self, other)\n' - 'object.__iand__(self, other)\n' - 'object.__ixor__(self, other)\n' - 'object.__ior__(self, other)\n' - '\n' - ' These methods are called to implement the augmented ' - 'arithmetic\n' - ' assignments ("+=", "-=", "*=", "@=", "/=", "//=", "%=", ' - '"**=",\n' - ' "<<=", ">>=", "&=", "^=", "|="). These methods should ' - 'attempt to\n' - ' do the operation in-place (modifying *self*) and return ' - 'the result\n' - ' (which could be, but does not have to be, *self*). If a ' - 'specific\n' - ' method is not defined, the augmented assignment falls ' - 'back to the\n' - ' normal methods. For instance, if *x* is an instance of ' - 'a class\n' - ' with an "__iadd__()" method, "x += y" is equivalent to ' - '"x =\n' - ' x.__iadd__(y)" . Otherwise, "x.__add__(y)" and ' - '"y.__radd__(x)" are\n' - ' considered, as with the evaluation of "x + y". In ' - 'certain\n' - ' situations, augmented assignment can result in ' - 'unexpected errors\n' - ' (see Why does a_tuple[i] += [‘item’] raise an exception ' - 'when the\n' - ' addition works?), but this behavior is in fact part of ' - 'the data\n' - ' model.\n' - '\n' - 'object.__neg__(self)\n' - 'object.__pos__(self)\n' - 'object.__abs__(self)\n' - 'object.__invert__(self)\n' - '\n' - ' Called to implement the unary arithmetic operations ' - '("-", "+",\n' - ' "abs()" and "~").\n' - '\n' - 'object.__complex__(self)\n' - 'object.__int__(self)\n' - 'object.__float__(self)\n' - '\n' - ' Called to implement the built-in functions "complex()", ' - '"int()" and\n' - ' "float()". Should return a value of the appropriate ' - 'type.\n' - '\n' - 'object.__index__(self)\n' - '\n' - ' Called to implement "operator.index()", and whenever ' - 'Python needs\n' - ' to losslessly convert the numeric object to an integer ' - 'object (such\n' - ' as in slicing, or in the built-in "bin()", "hex()" and ' - '"oct()"\n' - ' functions). Presence of this method indicates that the ' - 'numeric\n' - ' object is an integer type. Must return an integer.\n' - '\n' - ' Note: In order to have a coherent integer type class, ' - 'when\n' - ' "__index__()" is defined "__int__()" should also be ' - 'defined, and\n' - ' both should return the same value.\n' - '\n' - 'object.__round__(self[, ndigits])\n' - 'object.__trunc__(self)\n' - 'object.__floor__(self)\n' - 'object.__ceil__(self)\n' - '\n' - ' Called to implement the built-in function "round()" and ' - '"math"\n' - ' functions "trunc()", "floor()" and "ceil()". Unless ' - '*ndigits* is\n' - ' passed to "__round__()" all these methods should return ' - 'the value\n' - ' of the object truncated to an "Integral" (typically an ' - '"int").\n' - '\n' - ' If "__int__()" is not defined then the built-in function ' - '"int()"\n' - ' falls back to "__trunc__()".\n', - 'objects': 'Objects, values and types\n' - '*************************\n' - '\n' - '*Objects* are Python’s abstraction for data. All data in a ' - 'Python\n' - 'program is represented by objects or by relations between ' - 'objects. (In\n' - 'a sense, and in conformance to Von Neumann’s model of a “stored\n' - 'program computer,” code is also represented by objects.)\n' - '\n' - 'Every object has an identity, a type and a value. An object’s\n' - '*identity* never changes once it has been created; you may think ' - 'of it\n' - 'as the object’s address in memory. The ‘"is"’ operator compares ' - 'the\n' - 'identity of two objects; the "id()" function returns an integer\n' - 'representing its identity.\n' - '\n' - '**CPython implementation detail:** For CPython, "id(x)" is the ' - 'memory\n' - 'address where "x" is stored.\n' - '\n' - 'An object’s type determines the operations that the object ' - 'supports\n' - '(e.g., “does it have a length?”) and also defines the possible ' - 'values\n' - 'for objects of that type. The "type()" function returns an ' - 'object’s\n' - 'type (which is an object itself). Like its identity, an ' - 'object’s\n' - '*type* is also unchangeable. [1]\n' - '\n' - 'The *value* of some objects can change. Objects whose value can\n' - 'change are said to be *mutable*; objects whose value is ' - 'unchangeable\n' - 'once they are created are called *immutable*. (The value of an\n' - 'immutable container object that contains a reference to a ' - 'mutable\n' - 'object can change when the latter’s value is changed; however ' - 'the\n' - 'container is still considered immutable, because the collection ' - 'of\n' - 'objects it contains cannot be changed. So, immutability is not\n' - 'strictly the same as having an unchangeable value, it is more ' - 'subtle.)\n' - 'An object’s mutability is determined by its type; for instance,\n' - 'numbers, strings and tuples are immutable, while dictionaries ' - 'and\n' - 'lists are mutable.\n' - '\n' - 'Objects are never explicitly destroyed; however, when they ' - 'become\n' - 'unreachable they may be garbage-collected. An implementation is\n' - 'allowed to postpone garbage collection or omit it altogether — it ' - 'is a\n' - 'matter of implementation quality how garbage collection is\n' - 'implemented, as long as no objects are collected that are still\n' - 'reachable.\n' - '\n' - '**CPython implementation detail:** CPython currently uses a ' - 'reference-\n' - 'counting scheme with (optional) delayed detection of cyclically ' - 'linked\n' - 'garbage, which collects most objects as soon as they become\n' - 'unreachable, but is not guaranteed to collect garbage containing\n' - 'circular references. See the documentation of the "gc" module ' - 'for\n' - 'information on controlling the collection of cyclic garbage. ' - 'Other\n' - 'implementations act differently and CPython may change. Do not ' - 'depend\n' - 'on immediate finalization of objects when they become unreachable ' - '(so\n' - 'you should always close files explicitly).\n' - '\n' - 'Note that the use of the implementation’s tracing or debugging\n' - 'facilities may keep objects alive that would normally be ' - 'collectable.\n' - 'Also note that catching an exception with a ‘"try"…"except"’ ' - 'statement\n' - 'may keep objects alive.\n' - '\n' - 'Some objects contain references to “external” resources such as ' - 'open\n' - 'files or windows. It is understood that these resources are ' - 'freed\n' - 'when the object is garbage-collected, but since garbage ' - 'collection is\n' - 'not guaranteed to happen, such objects also provide an explicit ' - 'way to\n' - 'release the external resource, usually a "close()" method. ' - 'Programs\n' - 'are strongly recommended to explicitly close such objects. The\n' - '‘"try"…"finally"’ statement and the ‘"with"’ statement provide\n' - 'convenient ways to do this.\n' - '\n' - 'Some objects contain references to other objects; these are ' - 'called\n' - '*containers*. Examples of containers are tuples, lists and\n' - 'dictionaries. The references are part of a container’s value. ' - 'In\n' - 'most cases, when we talk about the value of a container, we imply ' - 'the\n' - 'values, not the identities of the contained objects; however, ' - 'when we\n' - 'talk about the mutability of a container, only the identities of ' - 'the\n' - 'immediately contained objects are implied. So, if an immutable\n' - 'container (like a tuple) contains a reference to a mutable ' - 'object, its\n' - 'value changes if that mutable object is changed.\n' - '\n' - 'Types affect almost all aspects of object behavior. Even the\n' - 'importance of object identity is affected in some sense: for ' - 'immutable\n' - 'types, operations that compute new values may actually return a\n' - 'reference to any existing object with the same type and value, ' - 'while\n' - 'for mutable objects this is not allowed. E.g., after "a = 1; b = ' - '1",\n' - '"a" and "b" may or may not refer to the same object with the ' - 'value\n' - 'one, depending on the implementation, but after "c = []; d = []", ' - '"c"\n' - 'and "d" are guaranteed to refer to two different, unique, newly\n' - 'created empty lists. (Note that "c = d = []" assigns the same ' - 'object\n' - 'to both "c" and "d".)\n', - 'operator-summary': 'Operator precedence\n' - '*******************\n' - '\n' - 'The following table summarizes the operator precedence ' - 'in Python, from\n' - 'lowest precedence (least binding) to highest precedence ' - '(most\n' - 'binding). Operators in the same box have the same ' - 'precedence. Unless\n' - 'the syntax is explicitly given, operators are binary. ' - 'Operators in\n' - 'the same box group left to right (except for ' - 'exponentiation, which\n' - 'groups from right to left).\n' - '\n' - 'Note that comparisons, membership tests, and identity ' - 'tests, all have\n' - 'the same precedence and have a left-to-right chaining ' - 'feature as\n' - 'described in the Comparisons section.\n' - '\n' - '+-------------------------------------------------+---------------------------------------+\n' - '| Operator | ' - 'Description |\n' - '+=================================================+=======================================+\n' - '| "lambda" | ' - 'Lambda expression |\n' - '+-------------------------------------------------+---------------------------------------+\n' - '| "if" – "else" | ' - 'Conditional expression |\n' - '+-------------------------------------------------+---------------------------------------+\n' - '| "or" | ' - 'Boolean OR |\n' - '+-------------------------------------------------+---------------------------------------+\n' - '| "and" | ' - 'Boolean AND |\n' - '+-------------------------------------------------+---------------------------------------+\n' - '| "not" "x" | ' - 'Boolean NOT |\n' - '+-------------------------------------------------+---------------------------------------+\n' - '| "in", "not in", "is", "is not", "<", "<=", ">", | ' - 'Comparisons, including membership |\n' - '| ">=", "!=", "==" | ' - 'tests and identity tests |\n' - '+-------------------------------------------------+---------------------------------------+\n' - '| "|" | ' - 'Bitwise OR |\n' - '+-------------------------------------------------+---------------------------------------+\n' - '| "^" | ' - 'Bitwise XOR |\n' - '+-------------------------------------------------+---------------------------------------+\n' - '| "&" | ' - 'Bitwise AND |\n' - '+-------------------------------------------------+---------------------------------------+\n' - '| "<<", ">>" | ' - 'Shifts |\n' - '+-------------------------------------------------+---------------------------------------+\n' - '| "+", "-" | ' - 'Addition and subtraction |\n' - '+-------------------------------------------------+---------------------------------------+\n' - '| "*", "@", "/", "//", "%" | ' - 'Multiplication, matrix |\n' - '| | ' - 'multiplication, division, floor |\n' - '| | ' - 'division, remainder [5] |\n' - '+-------------------------------------------------+---------------------------------------+\n' - '| "+x", "-x", "~x" | ' - 'Positive, negative, bitwise NOT |\n' - '+-------------------------------------------------+---------------------------------------+\n' - '| "**" | ' - 'Exponentiation [6] |\n' - '+-------------------------------------------------+---------------------------------------+\n' - '| "await" "x" | ' - 'Await expression |\n' - '+-------------------------------------------------+---------------------------------------+\n' - '| "x[index]", "x[index:index]", | ' - 'Subscription, slicing, call, |\n' - '| "x(arguments...)", "x.attribute" | ' - 'attribute reference |\n' - '+-------------------------------------------------+---------------------------------------+\n' - '| "(expressions...)", "[expressions...]", "{key: | ' - 'Binding or tuple display, list |\n' - '| value...}", "{expressions...}" | ' - 'display, dictionary display, set |\n' - '| | ' - 'display |\n' - '+-------------------------------------------------+---------------------------------------+\n' - '\n' - '-[ Footnotes ]-\n' - '\n' - '[1] While "abs(x%y) < abs(y)" is true mathematically, ' - 'for floats\n' - ' it may not be true numerically due to roundoff. For ' - 'example, and\n' - ' assuming a platform on which a Python float is an ' - 'IEEE 754 double-\n' - ' precision number, in order that "-1e-100 % 1e100" ' - 'have the same\n' - ' sign as "1e100", the computed result is "-1e-100 + ' - '1e100", which\n' - ' is numerically exactly equal to "1e100". The ' - 'function\n' - ' "math.fmod()" returns a result whose sign matches ' - 'the sign of the\n' - ' first argument instead, and so returns "-1e-100" in ' - 'this case.\n' - ' Which approach is more appropriate depends on the ' - 'application.\n' - '\n' - '[2] If x is very close to an exact integer multiple of ' - 'y, it’s\n' - ' possible for "x//y" to be one larger than ' - '"(x-x%y)//y" due to\n' - ' rounding. In such cases, Python returns the latter ' - 'result, in\n' - ' order to preserve that "divmod(x,y)[0] * y + x % y" ' - 'be very close\n' - ' to "x".\n' - '\n' - '[3] The Unicode standard distinguishes between *code ' - 'points* (e.g.\n' - ' U+0041) and *abstract characters* (e.g. “LATIN ' - 'CAPITAL LETTER A”).\n' - ' While most abstract characters in Unicode are only ' - 'represented\n' - ' using one code point, there is a number of abstract ' - 'characters\n' - ' that can in addition be represented using a sequence ' - 'of more than\n' - ' one code point. For example, the abstract character ' - '“LATIN\n' - ' CAPITAL LETTER C WITH CEDILLA” can be represented as ' - 'a single\n' - ' *precomposed character* at code position U+00C7, or ' - 'as a sequence\n' - ' of a *base character* at code position U+0043 (LATIN ' - 'CAPITAL\n' - ' LETTER C), followed by a *combining character* at ' - 'code position\n' - ' U+0327 (COMBINING CEDILLA).\n' - '\n' - ' The comparison operators on strings compare at the ' - 'level of\n' - ' Unicode code points. This may be counter-intuitive ' - 'to humans. For\n' - ' example, ""\\u00C7" == "\\u0043\\u0327"" is "False", ' - 'even though both\n' - ' strings represent the same abstract character “LATIN ' - 'CAPITAL\n' - ' LETTER C WITH CEDILLA”.\n' - '\n' - ' To compare strings at the level of abstract ' - 'characters (that is,\n' - ' in a way intuitive to humans), use ' - '"unicodedata.normalize()".\n' - '\n' - '[4] Due to automatic garbage-collection, free lists, and ' - 'the\n' - ' dynamic nature of descriptors, you may notice ' - 'seemingly unusual\n' - ' behaviour in certain uses of the "is" operator, like ' - 'those\n' - ' involving comparisons between instance methods, or ' - 'constants.\n' - ' Check their documentation for more info.\n' - '\n' - '[5] The "%" operator is also used for string formatting; ' - 'the same\n' - ' precedence applies.\n' - '\n' - '[6] The power operator "**" binds less tightly than an ' - 'arithmetic\n' - ' or bitwise unary operator on its right, that is, ' - '"2**-1" is "0.5".\n', - 'pass': 'The "pass" statement\n' - '********************\n' - '\n' - ' pass_stmt ::= "pass"\n' - '\n' - '"pass" is a null operation — when it is executed, nothing happens. ' - 'It\n' - 'is useful as a placeholder when a statement is required ' - 'syntactically,\n' - 'but no code needs to be executed, for example:\n' - '\n' - ' def f(arg): pass # a function that does nothing (yet)\n' - '\n' - ' class C: pass # a class with no methods (yet)\n', - 'power': 'The power operator\n' - '******************\n' - '\n' - 'The power operator binds more tightly than unary operators on its\n' - 'left; it binds less tightly than unary operators on its right. ' - 'The\n' - 'syntax is:\n' - '\n' - ' power ::= (await_expr | primary) ["**" u_expr]\n' - '\n' - 'Thus, in an unparenthesized sequence of power and unary operators, ' - 'the\n' - 'operators are evaluated from right to left (this does not ' - 'constrain\n' - 'the evaluation order for the operands): "-1**2" results in "-1".\n' - '\n' - 'The power operator has the same semantics as the built-in "pow()"\n' - 'function, when called with two arguments: it yields its left ' - 'argument\n' - 'raised to the power of its right argument. The numeric arguments ' - 'are\n' - 'first converted to a common type, and the result is of that type.\n' - '\n' - 'For int operands, the result has the same type as the operands ' - 'unless\n' - 'the second argument is negative; in that case, all arguments are\n' - 'converted to float and a float result is delivered. For example,\n' - '"10**2" returns "100", but "10**-2" returns "0.01".\n' - '\n' - 'Raising "0.0" to a negative power results in a ' - '"ZeroDivisionError".\n' - 'Raising a negative number to a fractional power results in a ' - '"complex"\n' - 'number. (In earlier versions it raised a "ValueError".)\n', - 'raise': 'The "raise" statement\n' - '*********************\n' - '\n' - ' raise_stmt ::= "raise" [expression ["from" expression]]\n' - '\n' - 'If no expressions are present, "raise" re-raises the last ' - 'exception\n' - 'that was active in the current scope. If no exception is active ' - 'in\n' - 'the current scope, a "RuntimeError" exception is raised indicating\n' - 'that this is an error.\n' - '\n' - 'Otherwise, "raise" evaluates the first expression as the exception\n' - 'object. It must be either a subclass or an instance of\n' - '"BaseException". If it is a class, the exception instance will be\n' - 'obtained when needed by instantiating the class with no arguments.\n' - '\n' - 'The *type* of the exception is the exception instance’s class, the\n' - '*value* is the instance itself.\n' - '\n' - 'A traceback object is normally created automatically when an ' - 'exception\n' - 'is raised and attached to it as the "__traceback__" attribute, ' - 'which\n' - 'is writable. You can create an exception and set your own traceback ' - 'in\n' - 'one step using the "with_traceback()" exception method (which ' - 'returns\n' - 'the same exception instance, with its traceback set to its ' - 'argument),\n' - 'like so:\n' - '\n' - ' raise Exception("foo occurred").with_traceback(tracebackobj)\n' - '\n' - 'The "from" clause is used for exception chaining: if given, the ' - 'second\n' - '*expression* must be another exception class or instance, which ' - 'will\n' - 'then be attached to the raised exception as the "__cause__" ' - 'attribute\n' - '(which is writable). If the raised exception is not handled, both\n' - 'exceptions will be printed:\n' - '\n' - ' >>> try:\n' - ' ... print(1 / 0)\n' - ' ... except Exception as exc:\n' - ' ... raise RuntimeError("Something bad happened") from exc\n' - ' ...\n' - ' Traceback (most recent call last):\n' - ' File "", line 2, in \n' - ' ZeroDivisionError: division by zero\n' - '\n' - ' The above exception was the direct cause of the following ' - 'exception:\n' - '\n' - ' Traceback (most recent call last):\n' - ' File "", line 4, in \n' - ' RuntimeError: Something bad happened\n' - '\n' - 'A similar mechanism works implicitly if an exception is raised ' - 'inside\n' - 'an exception handler or a "finally" clause: the previous exception ' - 'is\n' - 'then attached as the new exception’s "__context__" attribute:\n' - '\n' - ' >>> try:\n' - ' ... print(1 / 0)\n' - ' ... except:\n' - ' ... raise RuntimeError("Something bad happened")\n' - ' ...\n' - ' Traceback (most recent call last):\n' - ' File "", line 2, in \n' - ' ZeroDivisionError: division by zero\n' - '\n' - ' During handling of the above exception, another exception ' - 'occurred:\n' - '\n' - ' Traceback (most recent call last):\n' - ' File "", line 4, in \n' - ' RuntimeError: Something bad happened\n' - '\n' - 'Exception chaining can be explicitly suppressed by specifying ' - '"None"\n' - 'in the "from" clause:\n' - '\n' - ' >>> try:\n' - ' ... print(1 / 0)\n' - ' ... except:\n' - ' ... raise RuntimeError("Something bad happened") from None\n' - ' ...\n' - ' Traceback (most recent call last):\n' - ' File "", line 4, in \n' - ' RuntimeError: Something bad happened\n' - '\n' - 'Additional information on exceptions can be found in section\n' - 'Exceptions, and information about handling exceptions is in ' - 'section\n' - 'The try statement.\n' - '\n' - 'Changed in version 3.3: "None" is now permitted as "Y" in "raise X\n' - 'from Y".\n' - '\n' - 'New in version 3.3: The "__suppress_context__" attribute to ' - 'suppress\n' - 'automatic display of the exception context.\n', - 'return': 'The "return" statement\n' - '**********************\n' - '\n' - ' return_stmt ::= "return" [expression_list]\n' - '\n' - '"return" may only occur syntactically nested in a function ' - 'definition,\n' - 'not within a nested class definition.\n' - '\n' - 'If an expression list is present, it is evaluated, else "None" is\n' - 'substituted.\n' - '\n' - '"return" leaves the current function call with the expression list ' - '(or\n' - '"None") as return value.\n' - '\n' - 'When "return" passes control out of a "try" statement with a ' - '"finally"\n' - 'clause, that "finally" clause is executed before really leaving ' - 'the\n' - 'function.\n' - '\n' - 'In a generator function, the "return" statement indicates that ' - 'the\n' - 'generator is done and will cause "StopIteration" to be raised. ' - 'The\n' - 'returned value (if any) is used as an argument to construct\n' - '"StopIteration" and becomes the "StopIteration.value" attribute.\n' - '\n' - 'In an asynchronous generator function, an empty "return" ' - 'statement\n' - 'indicates that the asynchronous generator is done and will cause\n' - '"StopAsyncIteration" to be raised. A non-empty "return" statement ' - 'is\n' - 'a syntax error in an asynchronous generator function.\n', - 'sequence-types': 'Emulating container types\n' - '*************************\n' - '\n' - 'The following methods can be defined to implement ' - 'container objects.\n' - 'Containers usually are sequences (such as lists or tuples) ' - 'or mappings\n' - '(like dictionaries), but can represent other containers as ' - 'well. The\n' - 'first set of methods is used either to emulate a sequence ' - 'or to\n' - 'emulate a mapping; the difference is that for a sequence, ' + 'The "|" operator yields the bitwise (inclusive) OR of its ' + 'arguments,\n' + 'which must be integers or one of them must be a custom object\n' + 'overriding "__or__()" or "__ror__()" special methods.\n', + 'bltin-code-objects': 'Code Objects\n' + '************\n' + '\n' + 'Code objects are used by the implementation to ' + 'represent “pseudo-\n' + 'compiled” executable Python code such as a function ' + 'body. They differ\n' + 'from function objects because they don’t contain a ' + 'reference to their\n' + 'global execution environment. Code objects are ' + 'returned by the built-\n' + 'in "compile()" function and can be extracted from ' + 'function objects\n' + 'through their "__code__" attribute. See also the ' + '"code" module.\n' + '\n' + 'Accessing "__code__" raises an auditing event ' + '"object.__getattr__"\n' + 'with arguments "obj" and ""__code__"".\n' + '\n' + 'A code object can be executed or evaluated by passing ' + 'it (instead of a\n' + 'source string) to the "exec()" or "eval()" built-in ' + 'functions.\n' + '\n' + 'See The standard type hierarchy for more ' + 'information.\n', + 'bltin-ellipsis-object': 'The Ellipsis Object\n' + '*******************\n' + '\n' + 'This object is commonly used by slicing (see ' + 'Slicings). It supports\n' + 'no special operations. There is exactly one ' + 'ellipsis object, named\n' + '"Ellipsis" (a built-in name). "type(Ellipsis)()" ' + 'produces the\n' + '"Ellipsis" singleton.\n' + '\n' + 'It is written as "Ellipsis" or "...".\n', + 'bltin-null-object': 'The Null Object\n' + '***************\n' + '\n' + 'This object is returned by functions that don’t ' + 'explicitly return a\n' + 'value. It supports no special operations. There is ' + 'exactly one null\n' + 'object, named "None" (a built-in name). "type(None)()" ' + 'produces the\n' + 'same singleton.\n' + '\n' + 'It is written as "None".\n', + 'bltin-type-objects': 'Type Objects\n' + '************\n' + '\n' + 'Type objects represent the various object types. An ' + 'object’s type is\n' + 'accessed by the built-in function "type()". There are ' + 'no special\n' + 'operations on types. The standard module "types" ' + 'defines names for\n' + 'all standard built-in types.\n' + '\n' + 'Types are written like this: "".\n', + 'booleans': 'Boolean operations\n' + '******************\n' + '\n' + ' or_test ::= and_test | or_test "or" and_test\n' + ' and_test ::= not_test | and_test "and" not_test\n' + ' not_test ::= comparison | "not" not_test\n' + '\n' + 'In the context of Boolean operations, and also when expressions ' + 'are\n' + 'used by control flow statements, the following values are ' + 'interpreted\n' + 'as false: "False", "None", numeric zero of all types, and empty\n' + 'strings and containers (including strings, tuples, lists,\n' + 'dictionaries, sets and frozensets). All other values are ' + 'interpreted\n' + 'as true. User-defined objects can customize their truth value ' + 'by\n' + 'providing a "__bool__()" method.\n' + '\n' + 'The operator "not" yields "True" if its argument is false, ' + '"False"\n' + 'otherwise.\n' + '\n' + 'The expression "x and y" first evaluates *x*; if *x* is false, ' + 'its\n' + 'value is returned; otherwise, *y* is evaluated and the resulting ' + 'value\n' + 'is returned.\n' + '\n' + 'The expression "x or y" first evaluates *x*; if *x* is true, its ' + 'value\n' + 'is returned; otherwise, *y* is evaluated and the resulting value ' + 'is\n' + 'returned.\n' + '\n' + 'Note that neither "and" nor "or" restrict the value and type ' + 'they\n' + 'return to "False" and "True", but rather return the last ' + 'evaluated\n' + 'argument. This is sometimes useful, e.g., if "s" is a string ' + 'that\n' + 'should be replaced by a default value if it is empty, the ' + 'expression\n' + '"s or \'foo\'" yields the desired value. Because "not" has to ' + 'create a\n' + 'new value, it returns a boolean value regardless of the type of ' + 'its\n' + 'argument (for example, "not \'foo\'" produces "False" rather ' + 'than "\'\'".)\n', + 'break': 'The "break" statement\n' + '*********************\n' + '\n' + ' break_stmt ::= "break"\n' + '\n' + '"break" may only occur syntactically nested in a "for" or "while"\n' + 'loop, but not nested in a function or class definition within that\n' + 'loop.\n' + '\n' + 'It terminates the nearest enclosing loop, skipping the optional ' + '"else"\n' + 'clause if the loop has one.\n' + '\n' + 'If a "for" loop is terminated by "break", the loop control target\n' + 'keeps its current value.\n' + '\n' + 'When "break" passes control out of a "try" statement with a ' + '"finally"\n' + 'clause, that "finally" clause is executed before really leaving ' 'the\n' - 'allowable keys should be the integers *k* for which "0 <= ' - 'k < N" where\n' - '*N* is the length of the sequence, or slice objects, which ' - 'define a\n' - 'range of items. It is also recommended that mappings ' - 'provide the\n' - 'methods "keys()", "values()", "items()", "get()", ' - '"clear()",\n' - '"setdefault()", "pop()", "popitem()", "copy()", and ' - '"update()"\n' - 'behaving similar to those for Python’s standard dictionary ' - 'objects.\n' - 'The "collections" module provides a "MutableMapping" ' - 'abstract base\n' - 'class to help create those methods from a base set of ' - '"__getitem__()",\n' - '"__setitem__()", "__delitem__()", and "keys()". Mutable ' - 'sequences\n' - 'should provide methods "append()", "count()", "index()", ' - '"extend()",\n' - '"insert()", "pop()", "remove()", "reverse()" and "sort()", ' - 'like Python\n' - 'standard list objects. Finally, sequence types should ' - 'implement\n' - 'addition (meaning concatenation) and multiplication ' - '(meaning\n' - 'repetition) by defining the methods "__add__()", ' - '"__radd__()",\n' - '"__iadd__()", "__mul__()", "__rmul__()" and "__imul__()" ' - 'described\n' - 'below; they should not define other numerical operators. ' - 'It is\n' - 'recommended that both mappings and sequences implement ' + 'loop.\n', + 'callable-types': 'Emulating callable objects\n' + '**************************\n' + '\n' + 'object.__call__(self[, args...])\n' + '\n' + ' Called when the instance is “called” as a function; if ' + 'this method\n' + ' is defined, "x(arg1, arg2, ...)" roughly translates to\n' + ' "type(x).__call__(x, arg1, ...)". The "object" class ' + 'itself does\n' + ' not provide this method.\n', + 'calls': 'Calls\n' + '*****\n' + '\n' + 'A call calls a callable object (e.g., a *function*) with a ' + 'possibly\n' + 'empty series of *arguments*:\n' + '\n' + ' call ::= primary "(" [argument_list [","] | ' + 'comprehension] ")"\n' + ' argument_list ::= positional_arguments ["," ' + 'starred_and_keywords]\n' + ' ["," keywords_arguments]\n' + ' | starred_and_keywords ["," ' + 'keywords_arguments]\n' + ' | keywords_arguments\n' + ' positional_arguments ::= positional_item ("," positional_item)*\n' + ' positional_item ::= assignment_expression | "*" expression\n' + ' starred_and_keywords ::= ("*" expression | keyword_item)\n' + ' ("," "*" expression | "," ' + 'keyword_item)*\n' + ' keywords_arguments ::= (keyword_item | "**" expression)\n' + ' ("," keyword_item | "," "**" ' + 'expression)*\n' + ' keyword_item ::= identifier "=" expression\n' + '\n' + 'An optional trailing comma may be present after the positional and\n' + 'keyword arguments but does not affect the semantics.\n' + '\n' + 'The primary must evaluate to a callable object (user-defined\n' + 'functions, built-in functions, methods of built-in objects, class\n' + 'objects, methods of class instances, and all objects having a\n' + '"__call__()" method are callable). All argument expressions are\n' + 'evaluated before the call is attempted. Please refer to section\n' + 'Function definitions for the syntax of formal *parameter* lists.\n' + '\n' + 'If keyword arguments are present, they are first converted to\n' + 'positional arguments, as follows. First, a list of unfilled slots ' + 'is\n' + 'created for the formal parameters. If there are N positional\n' + 'arguments, they are placed in the first N slots. Next, for each\n' + 'keyword argument, the identifier is used to determine the\n' + 'corresponding slot (if the identifier is the same as the first ' + 'formal\n' + 'parameter name, the first slot is used, and so on). If the slot ' + 'is\n' + 'already filled, a "TypeError" exception is raised. Otherwise, the\n' + 'argument is placed in the slot, filling it (even if the expression ' + 'is\n' + '"None", it fills the slot). When all arguments have been ' + 'processed,\n' + 'the slots that are still unfilled are filled with the ' + 'corresponding\n' + 'default value from the function definition. (Default values are\n' + 'calculated, once, when the function is defined; thus, a mutable ' + 'object\n' + 'such as a list or dictionary used as default value will be shared ' + 'by\n' + 'all calls that don’t specify an argument value for the ' + 'corresponding\n' + 'slot; this should usually be avoided.) If there are any unfilled\n' + 'slots for which no default value is specified, a "TypeError" ' + 'exception\n' + 'is raised. Otherwise, the list of filled slots is used as the\n' + 'argument list for the call.\n' + '\n' + '**CPython implementation detail:** An implementation may provide\n' + 'built-in functions whose positional parameters do not have names, ' + 'even\n' + 'if they are ‘named’ for the purpose of documentation, and which\n' + 'therefore cannot be supplied by keyword. In CPython, this is the ' + 'case\n' + 'for functions implemented in C that use "PyArg_ParseTuple()" to ' + 'parse\n' + 'their arguments.\n' + '\n' + 'If there are more positional arguments than there are formal ' + 'parameter\n' + 'slots, a "TypeError" exception is raised, unless a formal ' + 'parameter\n' + 'using the syntax "*identifier" is present; in this case, that ' + 'formal\n' + 'parameter receives a tuple containing the excess positional ' + 'arguments\n' + '(or an empty tuple if there were no excess positional arguments).\n' + '\n' + 'If any keyword argument does not correspond to a formal parameter\n' + 'name, a "TypeError" exception is raised, unless a formal parameter\n' + 'using the syntax "**identifier" is present; in this case, that ' + 'formal\n' + 'parameter receives a dictionary containing the excess keyword\n' + 'arguments (using the keywords as keys and the argument values as\n' + 'corresponding values), or a (new) empty dictionary if there were ' + 'no\n' + 'excess keyword arguments.\n' + '\n' + 'If the syntax "*expression" appears in the function call, ' + '"expression"\n' + 'must evaluate to an *iterable*. Elements from these iterables are\n' + 'treated as if they were additional positional arguments. For the ' + 'call\n' + '"f(x1, x2, *y, x3, x4)", if *y* evaluates to a sequence *y1*, …, ' + '*yM*,\n' + 'this is equivalent to a call with M+4 positional arguments *x1*, ' + '*x2*,\n' + '*y1*, …, *yM*, *x3*, *x4*.\n' + '\n' + 'A consequence of this is that although the "*expression" syntax ' + 'may\n' + 'appear *after* explicit keyword arguments, it is processed ' + '*before*\n' + 'the keyword arguments (and any "**expression" arguments – see ' + 'below).\n' + 'So:\n' + '\n' + ' >>> def f(a, b):\n' + ' ... print(a, b)\n' + ' ...\n' + ' >>> f(b=1, *(2,))\n' + ' 2 1\n' + ' >>> f(a=1, *(2,))\n' + ' Traceback (most recent call last):\n' + ' File "", line 1, in \n' + " TypeError: f() got multiple values for keyword argument 'a'\n" + ' >>> f(1, *(2,))\n' + ' 1 2\n' + '\n' + 'It is unusual for both keyword arguments and the "*expression" ' + 'syntax\n' + 'to be used in the same call, so in practice this confusion does ' + 'not\n' + 'often arise.\n' + '\n' + 'If the syntax "**expression" appears in the function call,\n' + '"expression" must evaluate to a *mapping*, the contents of which ' + 'are\n' + 'treated as additional keyword arguments. If a parameter matching a ' + 'key\n' + 'has already been given a value (by an explicit keyword argument, ' + 'or\n' + 'from another unpacking), a "TypeError" exception is raised.\n' + '\n' + 'When "**expression" is used, each key in this mapping must be a\n' + 'string. Each value from the mapping is assigned to the first ' + 'formal\n' + 'parameter eligible for keyword assignment whose name is equal to ' 'the\n' - '"__contains__()" method to allow efficient use of the "in" ' - 'operator;\n' - 'for mappings, "in" should search the mapping’s keys; for ' - 'sequences, it\n' - 'should search through the values. It is further ' - 'recommended that both\n' - 'mappings and sequences implement the "__iter__()" method ' - 'to allow\n' - 'efficient iteration through the container; for mappings, ' - '"__iter__()"\n' - 'should be the same as "keys()"; for sequences, it should ' - 'iterate\n' - 'through the values.\n' - '\n' - 'object.__len__(self)\n' - '\n' - ' Called to implement the built-in function "len()". ' - 'Should return\n' - ' the length of the object, an integer ">=" 0. Also, an ' - 'object that\n' - ' doesn’t define a "__bool__()" method and whose ' - '"__len__()" method\n' - ' returns zero is considered to be false in a Boolean ' - 'context.\n' - '\n' - ' **CPython implementation detail:** In CPython, the ' - 'length is\n' - ' required to be at most "sys.maxsize". If the length is ' - 'larger than\n' - ' "sys.maxsize" some features (such as "len()") may ' - 'raise\n' - ' "OverflowError". To prevent raising "OverflowError" by ' - 'truth value\n' - ' testing, an object must define a "__bool__()" method.\n' - '\n' - 'object.__length_hint__(self)\n' - '\n' - ' Called to implement "operator.length_hint()". Should ' - 'return an\n' - ' estimated length for the object (which may be greater ' - 'or less than\n' - ' the actual length). The length must be an integer ">=" ' - '0. This\n' - ' method is purely an optimization and is never required ' - 'for\n' - ' correctness.\n' + 'key. A key need not be a Python identifier (e.g. ""max-temp °F"" ' + 'is\n' + 'acceptable, although it will not match any formal parameter that ' + 'could\n' + 'be declared). If there is no match to a formal parameter the ' + 'key-value\n' + 'pair is collected by the "**" parameter, if there is one, or if ' + 'there\n' + 'is not, a "TypeError" exception is raised.\n' + '\n' + 'Formal parameters using the syntax "*identifier" or "**identifier"\n' + 'cannot be used as positional argument slots or as keyword argument\n' + 'names.\n' '\n' - ' New in version 3.4.\n' + 'Changed in version 3.5: Function calls accept any number of "*" ' + 'and\n' + '"**" unpackings, positional arguments may follow iterable ' + 'unpackings\n' + '("*"), and keyword arguments may follow dictionary unpackings ' + '("**").\n' + 'Originally proposed by **PEP 448**.\n' '\n' - 'Note: Slicing is done exclusively with the following three ' - 'methods.\n' - ' A call like\n' + 'A call always returns some value, possibly "None", unless it raises ' + 'an\n' + 'exception. How this value is computed depends on the type of the\n' + 'callable object.\n' '\n' - ' a[1:2] = b\n' + 'If it is—\n' '\n' - ' is translated to\n' + 'a user-defined function:\n' + ' The code block for the function is executed, passing it the\n' + ' argument list. The first thing the code block will do is bind ' + 'the\n' + ' formal parameters to the arguments; this is described in ' + 'section\n' + ' Function definitions. When the code block executes a "return"\n' + ' statement, this specifies the return value of the function ' + 'call.\n' + ' If execution reaches the end of the code block without executing ' + 'a\n' + ' "return" statement, the return value is "None".\n' '\n' - ' a[slice(1, 2, None)] = b\n' + 'a built-in function or method:\n' + ' The result is up to the interpreter; see Built-in Functions for ' + 'the\n' + ' descriptions of built-in functions and methods.\n' '\n' - ' and so forth. Missing slice items are always filled in ' - 'with "None".\n' + 'a class object:\n' + ' A new instance of that class is returned.\n' '\n' - 'object.__getitem__(self, key)\n' + 'a class instance method:\n' + ' The corresponding user-defined function is called, with an ' + 'argument\n' + ' list that is one longer than the argument list of the call: the\n' + ' instance becomes the first argument.\n' '\n' - ' Called to implement evaluation of "self[key]". For ' - 'sequence types,\n' - ' the accepted keys should be integers and slice ' - 'objects. Note that\n' - ' the special interpretation of negative indexes (if the ' - 'class wishes\n' - ' to emulate a sequence type) is up to the ' - '"__getitem__()" method. If\n' - ' *key* is of an inappropriate type, "TypeError" may be ' - 'raised; if of\n' - ' a value outside the set of indexes for the sequence ' - '(after any\n' - ' special interpretation of negative values), ' - '"IndexError" should be\n' - ' raised. For mapping types, if *key* is missing (not in ' + 'a class instance:\n' + ' The class must define a "__call__()" method; the effect is then ' 'the\n' - ' container), "KeyError" should be raised.\n' - '\n' - ' Note: "for" loops expect that an "IndexError" will be ' - 'raised for\n' - ' illegal indexes to allow proper detection of the end ' - 'of the\n' - ' sequence.\n' - '\n' - 'object.__setitem__(self, key, value)\n' - '\n' - ' Called to implement assignment to "self[key]". Same ' - 'note as for\n' - ' "__getitem__()". This should only be implemented for ' - 'mappings if\n' - ' the objects support changes to the values for keys, or ' - 'if new keys\n' - ' can be added, or for sequences if elements can be ' - 'replaced. The\n' - ' same exceptions should be raised for improper *key* ' - 'values as for\n' - ' the "__getitem__()" method.\n' - '\n' - 'object.__delitem__(self, key)\n' - '\n' - ' Called to implement deletion of "self[key]". Same note ' - 'as for\n' - ' "__getitem__()". This should only be implemented for ' - 'mappings if\n' - ' the objects support removal of keys, or for sequences ' - 'if elements\n' - ' can be removed from the sequence. The same exceptions ' - 'should be\n' - ' raised for improper *key* values as for the ' - '"__getitem__()" method.\n' - '\n' - 'object.__missing__(self, key)\n' - '\n' - ' Called by "dict"."__getitem__()" to implement ' - '"self[key]" for dict\n' - ' subclasses when key is not in the dictionary.\n' - '\n' - 'object.__iter__(self)\n' - '\n' - ' This method is called when an iterator is required for ' - 'a container.\n' - ' This method should return a new iterator object that ' - 'can iterate\n' - ' over all the objects in the container. For mappings, ' - 'it should\n' - ' iterate over the keys of the container.\n' - '\n' - ' Iterator objects also need to implement this method; ' - 'they are\n' - ' required to return themselves. For more information on ' - 'iterator\n' - ' objects, see Iterator Types.\n' - '\n' - 'object.__reversed__(self)\n' - '\n' - ' Called (if present) by the "reversed()" built-in to ' - 'implement\n' - ' reverse iteration. It should return a new iterator ' - 'object that\n' - ' iterates over all the objects in the container in ' - 'reverse order.\n' - '\n' - ' If the "__reversed__()" method is not provided, the ' - '"reversed()"\n' - ' built-in will fall back to using the sequence protocol ' - '("__len__()"\n' - ' and "__getitem__()"). Objects that support the ' - 'sequence protocol\n' - ' should only provide "__reversed__()" if they can ' - 'provide an\n' - ' implementation that is more efficient than the one ' - 'provided by\n' - ' "reversed()".\n' - '\n' - 'The membership test operators ("in" and "not in") are ' - 'normally\n' - 'implemented as an iteration through a sequence. However, ' - 'container\n' - 'objects can supply the following special method with a ' - 'more efficient\n' - 'implementation, which also does not require the object be ' - 'a sequence.\n' - '\n' - 'object.__contains__(self, item)\n' - '\n' - ' Called to implement membership test operators. Should ' - 'return true\n' - ' if *item* is in *self*, false otherwise. For mapping ' - 'objects, this\n' - ' should consider the keys of the mapping rather than the ' - 'values or\n' - ' the key-item pairs.\n' - '\n' - ' For objects that don’t define "__contains__()", the ' - 'membership test\n' - ' first tries iteration via "__iter__()", then the old ' - 'sequence\n' - ' iteration protocol via "__getitem__()", see this ' - 'section in the\n' - ' language reference.\n', - 'shifting': 'Shifting operations\n' - '*******************\n' - '\n' - 'The shifting operations have lower priority than the arithmetic\n' - 'operations:\n' - '\n' - ' shift_expr ::= a_expr | shift_expr ("<<" | ">>") a_expr\n' - '\n' - 'These operators accept integers as arguments. They shift the ' - 'first\n' - 'argument to the left or right by the number of bits given by ' - 'the\n' - 'second argument.\n' - '\n' - 'A right shift by *n* bits is defined as floor division by ' - '"pow(2,n)".\n' - 'A left shift by *n* bits is defined as multiplication with ' - '"pow(2,n)".\n' - '\n' - 'Note: In the current implementation, the right-hand operand is\n' - ' required to be at most "sys.maxsize". If the right-hand ' - 'operand is\n' - ' larger than "sys.maxsize" an "OverflowError" exception is ' - 'raised.\n', - 'slicings': 'Slicings\n' - '********\n' - '\n' - 'A slicing selects a range of items in a sequence object (e.g., ' - 'a\n' - 'string, tuple or list). Slicings may be used as expressions or ' - 'as\n' - 'targets in assignment or "del" statements. The syntax for a ' - 'slicing:\n' - '\n' - ' slicing ::= primary "[" slice_list "]"\n' - ' slice_list ::= slice_item ("," slice_item)* [","]\n' - ' slice_item ::= expression | proper_slice\n' - ' proper_slice ::= [lower_bound] ":" [upper_bound] [ ":" ' - '[stride] ]\n' - ' lower_bound ::= expression\n' - ' upper_bound ::= expression\n' - ' stride ::= expression\n' - '\n' - 'There is ambiguity in the formal syntax here: anything that ' - 'looks like\n' - 'an expression list also looks like a slice list, so any ' - 'subscription\n' - 'can be interpreted as a slicing. Rather than further ' - 'complicating the\n' - 'syntax, this is disambiguated by defining that in this case the\n' - 'interpretation as a subscription takes priority over the\n' - 'interpretation as a slicing (this is the case if the slice list\n' - 'contains no proper slice).\n' - '\n' - 'The semantics for a slicing are as follows. The primary is ' - 'indexed\n' - '(using the same "__getitem__()" method as normal subscription) ' - 'with a\n' - 'key that is constructed from the slice list, as follows. If the ' - 'slice\n' - 'list contains at least one comma, the key is a tuple containing ' - 'the\n' - 'conversion of the slice items; otherwise, the conversion of the ' - 'lone\n' - 'slice item is the key. The conversion of a slice item that is ' - 'an\n' - 'expression is that expression. The conversion of a proper slice ' - 'is a\n' - 'slice object (see section The standard type hierarchy) whose ' - '"start",\n' - '"stop" and "step" attributes are the values of the expressions ' - 'given\n' - 'as lower bound, upper bound and stride, respectively, ' - 'substituting\n' - '"None" for missing expressions.\n', - 'specialattrs': 'Special Attributes\n' - '******************\n' - '\n' - 'The implementation adds a few special read-only attributes ' - 'to several\n' - 'object types, where they are relevant. Some of these are ' - 'not reported\n' - 'by the "dir()" built-in function.\n' - '\n' - 'object.__dict__\n' - '\n' - ' A dictionary or other mapping object used to store an ' - 'object’s\n' - ' (writable) attributes.\n' - '\n' - 'instance.__class__\n' - '\n' - ' The class to which a class instance belongs.\n' - '\n' - 'class.__bases__\n' - '\n' - ' The tuple of base classes of a class object.\n' - '\n' - 'definition.__name__\n' - '\n' - ' The name of the class, function, method, descriptor, or ' - 'generator\n' - ' instance.\n' - '\n' - 'definition.__qualname__\n' - '\n' - ' The *qualified name* of the class, function, method, ' - 'descriptor, or\n' - ' generator instance.\n' - '\n' - ' New in version 3.3.\n' - '\n' - 'class.__mro__\n' - '\n' - ' This attribute is a tuple of classes that are considered ' - 'when\n' - ' looking for base classes during method resolution.\n' - '\n' - 'class.mro()\n' - '\n' - ' This method can be overridden by a metaclass to customize ' - 'the\n' - ' method resolution order for its instances. It is called ' - 'at class\n' - ' instantiation, and its result is stored in "__mro__".\n' - '\n' - 'class.__subclasses__()\n' - '\n' - ' Each class keeps a list of weak references to its ' - 'immediate\n' - ' subclasses. This method returns a list of all those ' - 'references\n' - ' still alive. Example:\n' - '\n' - ' >>> int.__subclasses__()\n' - " []\n" - '\n' - '-[ Footnotes ]-\n' - '\n' - '[1] Additional information on these special methods may be ' - 'found\n' - ' in the Python Reference Manual (Basic customization).\n' - '\n' - '[2] As a consequence, the list "[1, 2]" is considered equal ' - 'to\n' - ' "[1.0, 2.0]", and similarly for tuples.\n' - '\n' - '[3] They must have since the parser can’t tell the type of ' - 'the\n' - ' operands.\n' - '\n' - '[4] Cased characters are those with general category ' - 'property\n' - ' being one of “Lu” (Letter, uppercase), “Ll” (Letter, ' - 'lowercase),\n' - ' or “Lt” (Letter, titlecase).\n' - '\n' - '[5] To format only a tuple you should therefore provide a\n' - ' singleton tuple whose only element is the tuple to be ' - 'formatted.\n', - 'specialnames': 'Special method names\n' - '********************\n' - '\n' - 'A class can implement certain operations that are invoked by ' - 'special\n' - 'syntax (such as arithmetic operations or subscripting and ' - 'slicing) by\n' - 'defining methods with special names. This is Python’s ' - 'approach to\n' - '*operator overloading*, allowing classes to define their own ' - 'behavior\n' - 'with respect to language operators. For instance, if a ' - 'class defines\n' - 'a method named "__getitem__()", and "x" is an instance of ' - 'this class,\n' - 'then "x[i]" is roughly equivalent to "type(x).__getitem__(x, ' - 'i)".\n' - 'Except where mentioned, attempts to execute an operation ' - 'raise an\n' - 'exception when no appropriate method is defined (typically\n' - '"AttributeError" or "TypeError").\n' - '\n' - 'Setting a special method to "None" indicates that the ' - 'corresponding\n' - 'operation is not available. For example, if a class sets ' - '"__iter__()"\n' - 'to "None", the class is not iterable, so calling "iter()" on ' - 'its\n' - 'instances will raise a "TypeError" (without falling back to\n' - '"__getitem__()"). [2]\n' - '\n' - 'When implementing a class that emulates any built-in type, ' - 'it is\n' - 'important that the emulation only be implemented to the ' - 'degree that it\n' - 'makes sense for the object being modelled. For example, ' - 'some\n' - 'sequences may work well with retrieval of individual ' - 'elements, but\n' - 'extracting a slice may not make sense. (One example of this ' - 'is the\n' - '"NodeList" interface in the W3C’s Document Object Model.)\n' - '\n' - '\n' - 'Basic customization\n' - '===================\n' - '\n' - 'object.__new__(cls[, ...])\n' - '\n' - ' Called to create a new instance of class *cls*. ' - '"__new__()" is a\n' - ' static method (special-cased so you need not declare it ' - 'as such)\n' - ' that takes the class of which an instance was requested ' - 'as its\n' - ' first argument. The remaining arguments are those passed ' - 'to the\n' - ' object constructor expression (the call to the class). ' - 'The return\n' - ' value of "__new__()" should be the new object instance ' - '(usually an\n' - ' instance of *cls*).\n' - '\n' - ' Typical implementations create a new instance of the ' - 'class by\n' - ' invoking the superclass’s "__new__()" method using\n' - ' "super().__new__(cls[, ...])" with appropriate arguments ' - 'and then\n' - ' modifying the newly-created instance as necessary before ' - 'returning\n' - ' it.\n' - '\n' - ' If "__new__()" returns an instance of *cls*, then the ' - 'new\n' - ' instance’s "__init__()" method will be invoked like\n' - ' "__init__(self[, ...])", where *self* is the new instance ' - 'and the\n' - ' remaining arguments are the same as were passed to ' - '"__new__()".\n' - '\n' - ' If "__new__()" does not return an instance of *cls*, then ' - 'the new\n' - ' instance’s "__init__()" method will not be invoked.\n' - '\n' - ' "__new__()" is intended mainly to allow subclasses of ' - 'immutable\n' - ' types (like int, str, or tuple) to customize instance ' - 'creation. It\n' - ' is also commonly overridden in custom metaclasses in ' - 'order to\n' - ' customize class creation.\n' - '\n' - 'object.__init__(self[, ...])\n' - '\n' - ' Called after the instance has been created (by ' - '"__new__()"), but\n' - ' before it is returned to the caller. The arguments are ' - 'those\n' - ' passed to the class constructor expression. If a base ' - 'class has an\n' - ' "__init__()" method, the derived class’s "__init__()" ' - 'method, if\n' - ' any, must explicitly call it to ensure proper ' - 'initialization of the\n' - ' base class part of the instance; for example:\n' - ' "super().__init__([args...])".\n' - '\n' - ' Because "__new__()" and "__init__()" work together in ' - 'constructing\n' - ' objects ("__new__()" to create it, and "__init__()" to ' - 'customize\n' - ' it), no non-"None" value may be returned by "__init__()"; ' - 'doing so\n' - ' will cause a "TypeError" to be raised at runtime.\n' - '\n' - 'object.__del__(self)\n' - '\n' - ' Called when the instance is about to be destroyed. This ' - 'is also\n' - ' called a finalizer or (improperly) a destructor. If a ' - 'base class\n' - ' has a "__del__()" method, the derived class’s "__del__()" ' - 'method,\n' - ' if any, must explicitly call it to ensure proper deletion ' - 'of the\n' - ' base class part of the instance.\n' - '\n' - ' It is possible (though not recommended!) for the ' - '"__del__()" method\n' - ' to postpone destruction of the instance by creating a new ' - 'reference\n' - ' to it. This is called object *resurrection*. It is\n' - ' implementation-dependent whether "__del__()" is called a ' - 'second\n' - ' time when a resurrected object is about to be destroyed; ' - 'the\n' - ' current *CPython* implementation only calls it once.\n' - '\n' - ' It is not guaranteed that "__del__()" methods are called ' - 'for\n' - ' objects that still exist when the interpreter exits.\n' - '\n' - ' Note: "del x" doesn’t directly call "x.__del__()" — the ' - 'former\n' - ' decrements the reference count for "x" by one, and the ' - 'latter is\n' - ' only called when "x"’s reference count reaches zero.\n' - '\n' - ' **CPython implementation detail:** It is possible for a ' - 'reference\n' - ' cycle to prevent the reference count of an object from ' - 'going to\n' - ' zero. In this case, the cycle will be later detected and ' - 'deleted\n' - ' by the *cyclic garbage collector*. A common cause of ' - 'reference\n' - ' cycles is when an exception has been caught in a local ' - 'variable.\n' - ' The frame’s locals then reference the exception, which ' - 'references\n' - ' its own traceback, which references the locals of all ' - 'frames caught\n' - ' in the traceback.\n' - '\n' - ' See also: Documentation for the "gc" module.\n' - '\n' - ' Warning: Due to the precarious circumstances under which\n' - ' "__del__()" methods are invoked, exceptions that occur ' - 'during\n' - ' their execution are ignored, and a warning is printed ' - 'to\n' - ' "sys.stderr" instead. In particular:\n' - '\n' - ' * "__del__()" can be invoked when arbitrary code is ' - 'being\n' - ' executed, including from any arbitrary thread. If ' - '"__del__()"\n' - ' needs to take a lock or invoke any other blocking ' - 'resource, it\n' - ' may deadlock as the resource may already be taken by ' - 'the code\n' - ' that gets interrupted to execute "__del__()".\n' - '\n' - ' * "__del__()" can be executed during interpreter ' - 'shutdown. As\n' - ' a consequence, the global variables it needs to ' - 'access\n' - ' (including other modules) may already have been ' - 'deleted or set\n' - ' to "None". Python guarantees that globals whose name ' - 'begins\n' - ' with a single underscore are deleted from their ' - 'module before\n' - ' other globals are deleted; if no other references to ' - 'such\n' - ' globals exist, this may help in assuring that ' - 'imported modules\n' - ' are still available at the time when the "__del__()" ' - 'method is\n' - ' called.\n' - '\n' - 'object.__repr__(self)\n' - '\n' - ' Called by the "repr()" built-in function to compute the ' - '“official”\n' - ' string representation of an object. If at all possible, ' - 'this\n' - ' should look like a valid Python expression that could be ' - 'used to\n' - ' recreate an object with the same value (given an ' - 'appropriate\n' - ' environment). If this is not possible, a string of the ' - 'form\n' - ' "<...some useful description...>" should be returned. The ' - 'return\n' - ' value must be a string object. If a class defines ' - '"__repr__()" but\n' - ' not "__str__()", then "__repr__()" is also used when an ' - '“informal”\n' - ' string representation of instances of that class is ' - 'required.\n' - '\n' - ' This is typically used for debugging, so it is important ' - 'that the\n' - ' representation is information-rich and unambiguous.\n' - '\n' - 'object.__str__(self)\n' - '\n' - ' Called by "str(object)" and the built-in functions ' - '"format()" and\n' - ' "print()" to compute the “informal” or nicely printable ' - 'string\n' - ' representation of an object. The return value must be a ' - 'string\n' - ' object.\n' - '\n' - ' This method differs from "object.__repr__()" in that ' - 'there is no\n' - ' expectation that "__str__()" return a valid Python ' - 'expression: a\n' - ' more convenient or concise representation can be used.\n' - '\n' - ' The default implementation defined by the built-in type ' - '"object"\n' - ' calls "object.__repr__()".\n' - '\n' - 'object.__bytes__(self)\n' - '\n' - ' Called by bytes to compute a byte-string representation ' - 'of an\n' - ' object. This should return a "bytes" object.\n' - '\n' - 'object.__format__(self, format_spec)\n' - '\n' - ' Called by the "format()" built-in function, and by ' - 'extension,\n' - ' evaluation of formatted string literals and the ' - '"str.format()"\n' - ' method, to produce a “formatted” string representation of ' - 'an\n' - ' object. The "format_spec" argument is a string that ' - 'contains a\n' - ' description of the formatting options desired. The ' - 'interpretation\n' - ' of the "format_spec" argument is up to the type ' - 'implementing\n' - ' "__format__()", however most classes will either ' - 'delegate\n' - ' formatting to one of the built-in types, or use a ' - 'similar\n' - ' formatting option syntax.\n' - '\n' - ' See Format Specification Mini-Language for a description ' - 'of the\n' - ' standard formatting syntax.\n' - '\n' - ' The return value must be a string object.\n' - '\n' - ' Changed in version 3.4: The __format__ method of "object" ' - 'itself\n' - ' raises a "TypeError" if passed any non-empty string.\n' - '\n' - 'object.__lt__(self, other)\n' - 'object.__le__(self, other)\n' - 'object.__eq__(self, other)\n' - 'object.__ne__(self, other)\n' - 'object.__gt__(self, other)\n' - 'object.__ge__(self, other)\n' - '\n' - ' These are the so-called “rich comparison” methods. The\n' - ' correspondence between operator symbols and method names ' - 'is as\n' - ' follows: "xy" calls\n' - ' "x.__gt__(y)", and "x>=y" calls "x.__ge__(y)".\n' - '\n' - ' A rich comparison method may return the singleton ' - '"NotImplemented"\n' - ' if it does not implement the operation for a given pair ' - 'of\n' - ' arguments. By convention, "False" and "True" are returned ' - 'for a\n' - ' successful comparison. However, these methods can return ' - 'any value,\n' - ' so if the comparison operator is used in a Boolean ' - 'context (e.g.,\n' - ' in the condition of an "if" statement), Python will call ' - '"bool()"\n' - ' on the value to determine if the result is true or ' - 'false.\n' - '\n' - ' By default, "__ne__()" delegates to "__eq__()" and ' - 'inverts the\n' - ' result unless it is "NotImplemented". There are no other ' - 'implied\n' - ' relationships among the comparison operators, for ' - 'example, the\n' - ' truth of "(x.__hash__".\n' - '\n' - ' If a class that does not override "__eq__()" wishes to ' - 'suppress\n' - ' hash support, it should include "__hash__ = None" in the ' - 'class\n' - ' definition. A class which defines its own "__hash__()" ' - 'that\n' - ' explicitly raises a "TypeError" would be incorrectly ' - 'identified as\n' - ' hashable by an "isinstance(obj, collections.Hashable)" ' - 'call.\n' - '\n' - ' Note: By default, the "__hash__()" values of str, bytes ' - 'and\n' - ' datetime objects are “salted” with an unpredictable ' - 'random value.\n' - ' Although they remain constant within an individual ' - 'Python\n' - ' process, they are not predictable between repeated ' - 'invocations of\n' - ' Python.This is intended to provide protection against a ' - 'denial-\n' - ' of-service caused by carefully-chosen inputs that ' - 'exploit the\n' - ' worst case performance of a dict insertion, O(n^2) ' - 'complexity.\n' - ' See http://www.ocert.org/advisories/ocert-2011-003.html ' - 'for\n' - ' details.Changing hash values affects the iteration ' - 'order of\n' - ' dicts, sets and other mappings. Python has never made ' - 'guarantees\n' - ' about this ordering (and it typically varies between ' - '32-bit and\n' - ' 64-bit builds).See also "PYTHONHASHSEED".\n' - '\n' - ' Changed in version 3.3: Hash randomization is enabled by ' - 'default.\n' - '\n' - 'object.__bool__(self)\n' - '\n' - ' Called to implement truth value testing and the built-in ' - 'operation\n' - ' "bool()"; should return "False" or "True". When this ' - 'method is not\n' - ' defined, "__len__()" is called, if it is defined, and the ' - 'object is\n' - ' considered true if its result is nonzero. If a class ' - 'defines\n' - ' neither "__len__()" nor "__bool__()", all its instances ' - 'are\n' - ' considered true.\n' - '\n' - '\n' - 'Customizing attribute access\n' - '============================\n' - '\n' - 'The following methods can be defined to customize the ' - 'meaning of\n' - 'attribute access (use of, assignment to, or deletion of ' - '"x.name") for\n' - 'class instances.\n' - '\n' - 'object.__getattr__(self, name)\n' - '\n' - ' Called when the default attribute access fails with an\n' - ' "AttributeError" (either "__getattribute__()" raises an\n' - ' "AttributeError" because *name* is not an instance ' - 'attribute or an\n' - ' attribute in the class tree for "self"; or "__get__()" of ' - 'a *name*\n' - ' property raises "AttributeError"). This method should ' - 'either\n' - ' return the (computed) attribute value or raise an ' - '"AttributeError"\n' - ' exception.\n' - '\n' - ' Note that if the attribute is found through the normal ' - 'mechanism,\n' - ' "__getattr__()" is not called. (This is an intentional ' - 'asymmetry\n' - ' between "__getattr__()" and "__setattr__()".) This is ' - 'done both for\n' - ' efficiency reasons and because otherwise "__getattr__()" ' - 'would have\n' - ' no way to access other attributes of the instance. Note ' - 'that at\n' - ' least for instance variables, you can fake total control ' - 'by not\n' - ' inserting any values in the instance attribute dictionary ' - '(but\n' - ' instead inserting them in another object). See the\n' - ' "__getattribute__()" method below for a way to actually ' - 'get total\n' - ' control over attribute access.\n' - '\n' - 'object.__getattribute__(self, name)\n' - '\n' - ' Called unconditionally to implement attribute accesses ' - 'for\n' - ' instances of the class. If the class also defines ' - '"__getattr__()",\n' - ' the latter will not be called unless "__getattribute__()" ' - 'either\n' - ' calls it explicitly or raises an "AttributeError". This ' - 'method\n' - ' should return the (computed) attribute value or raise an\n' - ' "AttributeError" exception. In order to avoid infinite ' - 'recursion in\n' - ' this method, its implementation should always call the ' - 'base class\n' - ' method with the same name to access any attributes it ' - 'needs, for\n' - ' example, "object.__getattribute__(self, name)".\n' - '\n' - ' Note: This method may still be bypassed when looking up ' - 'special\n' - ' methods as the result of implicit invocation via ' - 'language syntax\n' - ' or built-in functions. See Special method lookup.\n' - '\n' - 'object.__setattr__(self, name, value)\n' - '\n' - ' Called when an attribute assignment is attempted. This ' - 'is called\n' - ' instead of the normal mechanism (i.e. store the value in ' - 'the\n' - ' instance dictionary). *name* is the attribute name, ' - '*value* is the\n' - ' value to be assigned to it.\n' - '\n' - ' If "__setattr__()" wants to assign to an instance ' - 'attribute, it\n' - ' should call the base class method with the same name, for ' - 'example,\n' - ' "object.__setattr__(self, name, value)".\n' - '\n' - 'object.__delattr__(self, name)\n' - '\n' - ' Like "__setattr__()" but for attribute deletion instead ' - 'of\n' - ' assignment. This should only be implemented if "del ' - 'obj.name" is\n' - ' meaningful for the object.\n' - '\n' - 'object.__dir__(self)\n' - '\n' - ' Called when "dir()" is called on the object. A sequence ' - 'must be\n' - ' returned. "dir()" converts the returned sequence to a ' - 'list and\n' - ' sorts it.\n' - '\n' - '\n' - 'Customizing module attribute access\n' - '-----------------------------------\n' - '\n' - 'For a more fine grained customization of the module behavior ' - '(setting\n' - 'attributes, properties, etc.), one can set the "__class__" ' - 'attribute\n' - 'of a module object to a subclass of "types.ModuleType". For ' - 'example:\n' - '\n' - ' import sys\n' - ' from types import ModuleType\n' - '\n' - ' class VerboseModule(ModuleType):\n' - ' def __repr__(self):\n' - " return f'Verbose {self.__name__}'\n" - '\n' - ' def __setattr__(self, attr, value):\n' - " print(f'Setting {attr}...')\n" - ' setattr(self, attr, value)\n' - '\n' - ' sys.modules[__name__].__class__ = VerboseModule\n' - '\n' - 'Note: Setting module "__class__" only affects lookups made ' - 'using the\n' - ' attribute access syntax – directly accessing the module ' - 'globals\n' - ' (whether by code within the module, or via a reference to ' - 'the\n' - ' module’s globals dictionary) is unaffected.\n' - '\n' - 'Changed in version 3.5: "__class__" module attribute is now ' - 'writable.\n' - '\n' - '\n' - 'Implementing Descriptors\n' - '------------------------\n' - '\n' - 'The following methods only apply when an instance of the ' - 'class\n' - 'containing the method (a so-called *descriptor* class) ' - 'appears in an\n' - '*owner* class (the descriptor must be in either the owner’s ' - 'class\n' - 'dictionary or in the class dictionary for one of its ' - 'parents). In the\n' - 'examples below, “the attribute” refers to the attribute ' - 'whose name is\n' - 'the key of the property in the owner class’ "__dict__".\n' - '\n' - 'object.__get__(self, instance, owner)\n' - '\n' - ' Called to get the attribute of the owner class (class ' - 'attribute\n' - ' access) or of an instance of that class (instance ' - 'attribute\n' - ' access). *owner* is always the owner class, while ' - '*instance* is the\n' - ' instance that the attribute was accessed through, or ' - '"None" when\n' - ' the attribute is accessed through the *owner*. This ' - 'method should\n' - ' return the (computed) attribute value or raise an ' - '"AttributeError"\n' - ' exception.\n' - '\n' - 'object.__set__(self, instance, value)\n' - '\n' - ' Called to set the attribute on an instance *instance* of ' - 'the owner\n' - ' class to a new value, *value*.\n' - '\n' - 'object.__delete__(self, instance)\n' - '\n' - ' Called to delete the attribute on an instance *instance* ' - 'of the\n' - ' owner class.\n' - '\n' - 'object.__set_name__(self, owner, name)\n' - '\n' - ' Called at the time the owning class *owner* is created. ' - 'The\n' - ' descriptor has been assigned to *name*.\n' - '\n' - ' New in version 3.6.\n' - '\n' - 'The attribute "__objclass__" is interpreted by the "inspect" ' - 'module as\n' - 'specifying the class where this object was defined (setting ' - 'this\n' - 'appropriately can assist in runtime introspection of dynamic ' - 'class\n' - 'attributes). For callables, it may indicate that an instance ' - 'of the\n' - 'given type (or a subclass) is expected or required as the ' - 'first\n' - 'positional argument (for example, CPython sets this ' - 'attribute for\n' - 'unbound methods that are implemented in C).\n' - '\n' - '\n' - 'Invoking Descriptors\n' - '--------------------\n' - '\n' - 'In general, a descriptor is an object attribute with ' - '“binding\n' - 'behavior”, one whose attribute access has been overridden by ' - 'methods\n' - 'in the descriptor protocol: "__get__()", "__set__()", and\n' - '"__delete__()". If any of those methods are defined for an ' - 'object, it\n' - 'is said to be a descriptor.\n' - '\n' - 'The default behavior for attribute access is to get, set, or ' - 'delete\n' - 'the attribute from an object’s dictionary. For instance, ' - '"a.x" has a\n' - 'lookup chain starting with "a.__dict__[\'x\']", then\n' - '"type(a).__dict__[\'x\']", and continuing through the base ' - 'classes of\n' - '"type(a)" excluding metaclasses.\n' - '\n' - 'However, if the looked-up value is an object defining one of ' - 'the\n' - 'descriptor methods, then Python may override the default ' - 'behavior and\n' - 'invoke the descriptor method instead. Where this occurs in ' - 'the\n' - 'precedence chain depends on which descriptor methods were ' - 'defined and\n' - 'how they were called.\n' - '\n' - 'The starting point for descriptor invocation is a binding, ' - '"a.x". How\n' - 'the arguments are assembled depends on "a":\n' - '\n' - 'Direct Call\n' - ' The simplest and least common call is when user code ' - 'directly\n' - ' invokes a descriptor method: "x.__get__(a)".\n' - '\n' - 'Instance Binding\n' - ' If binding to an object instance, "a.x" is transformed ' - 'into the\n' - ' call: "type(a).__dict__[\'x\'].__get__(a, type(a))".\n' - '\n' - 'Class Binding\n' - ' If binding to a class, "A.x" is transformed into the ' - 'call:\n' - ' "A.__dict__[\'x\'].__get__(None, A)".\n' - '\n' - 'Super Binding\n' - ' If "a" is an instance of "super", then the binding ' - '"super(B,\n' - ' obj).m()" searches "obj.__class__.__mro__" for the base ' - 'class "A"\n' - ' immediately preceding "B" and then invokes the descriptor ' - 'with the\n' - ' call: "A.__dict__[\'m\'].__get__(obj, obj.__class__)".\n' - '\n' - 'For instance bindings, the precedence of descriptor ' - 'invocation depends\n' - 'on the which descriptor methods are defined. A descriptor ' - 'can define\n' - 'any combination of "__get__()", "__set__()" and ' - '"__delete__()". If it\n' - 'does not define "__get__()", then accessing the attribute ' - 'will return\n' - 'the descriptor object itself unless there is a value in the ' - 'object’s\n' - 'instance dictionary. If the descriptor defines "__set__()" ' - 'and/or\n' - '"__delete__()", it is a data descriptor; if it defines ' - 'neither, it is\n' - 'a non-data descriptor. Normally, data descriptors define ' - 'both\n' - '"__get__()" and "__set__()", while non-data descriptors have ' - 'just the\n' - '"__get__()" method. Data descriptors with "__set__()" and ' - '"__get__()"\n' - 'defined always override a redefinition in an instance ' - 'dictionary. In\n' - 'contrast, non-data descriptors can be overridden by ' - 'instances.\n' - '\n' - 'Python methods (including "staticmethod()" and ' - '"classmethod()") are\n' - 'implemented as non-data descriptors. Accordingly, instances ' - 'can\n' - 'redefine and override methods. This allows individual ' - 'instances to\n' - 'acquire behaviors that differ from other instances of the ' - 'same class.\n' - '\n' - 'The "property()" function is implemented as a data ' - 'descriptor.\n' - 'Accordingly, instances cannot override the behavior of a ' - 'property.\n' - '\n' - '\n' - '__slots__\n' - '---------\n' - '\n' - '*__slots__* allow us to explicitly declare data members ' - '(like\n' - 'properties) and deny the creation of *__dict__* and ' - '*__weakref__*\n' - '(unless explicitly declared in *__slots__* or available in a ' - 'parent.)\n' - '\n' - 'The space saved over using *__dict__* can be significant.\n' - '\n' - 'object.__slots__\n' - '\n' - ' This class variable can be assigned a string, iterable, ' - 'or sequence\n' - ' of strings with variable names used by instances. ' - '*__slots__*\n' - ' reserves space for the declared variables and prevents ' - 'the\n' - ' automatic creation of *__dict__* and *__weakref__* for ' - 'each\n' - ' instance.\n' - '\n' - '\n' - 'Notes on using *__slots__*\n' - '~~~~~~~~~~~~~~~~~~~~~~~~~~\n' - '\n' - '* When inheriting from a class without *__slots__*, the ' - '*__dict__*\n' - ' and *__weakref__* attribute of the instances will always ' - 'be\n' - ' accessible.\n' - '\n' - '* Without a *__dict__* variable, instances cannot be ' - 'assigned new\n' - ' variables not listed in the *__slots__* definition. ' - 'Attempts to\n' - ' assign to an unlisted variable name raises ' - '"AttributeError". If\n' - ' dynamic assignment of new variables is desired, then add\n' - ' "\'__dict__\'" to the sequence of strings in the ' - '*__slots__*\n' - ' declaration.\n' - '\n' - '* Without a *__weakref__* variable for each instance, ' - 'classes\n' - ' defining *__slots__* do not support weak references to ' - 'its\n' - ' instances. If weak reference support is needed, then add\n' - ' "\'__weakref__\'" to the sequence of strings in the ' - '*__slots__*\n' - ' declaration.\n' - '\n' - '* *__slots__* are implemented at the class level by ' - 'creating\n' - ' descriptors (Implementing Descriptors) for each variable ' - 'name. As a\n' - ' result, class attributes cannot be used to set default ' - 'values for\n' - ' instance variables defined by *__slots__*; otherwise, the ' - 'class\n' - ' attribute would overwrite the descriptor assignment.\n' - '\n' - '* The action of a *__slots__* declaration is not limited to ' - 'the\n' - ' class where it is defined. *__slots__* declared in ' - 'parents are\n' - ' available in child classes. However, child subclasses will ' - 'get a\n' - ' *__dict__* and *__weakref__* unless they also define ' - '*__slots__*\n' - ' (which should only contain names of any *additional* ' - 'slots).\n' - '\n' - '* If a class defines a slot also defined in a base class, ' - 'the\n' - ' instance variable defined by the base class slot is ' - 'inaccessible\n' - ' (except by retrieving its descriptor directly from the ' - 'base class).\n' - ' This renders the meaning of the program undefined. In the ' - 'future, a\n' - ' check may be added to prevent this.\n' - '\n' - '* Nonempty *__slots__* does not work for classes derived ' - 'from\n' - ' “variable-length” built-in types such as "int", "bytes" ' - 'and "tuple".\n' - '\n' - '* Any non-string iterable may be assigned to *__slots__*. ' - 'Mappings\n' - ' may also be used; however, in the future, special meaning ' - 'may be\n' - ' assigned to the values corresponding to each key.\n' - '\n' - '* *__class__* assignment works only if both classes have the ' - 'same\n' - ' *__slots__*.\n' - '\n' - '* Multiple inheritance with multiple slotted parent classes ' - 'can be\n' - ' used, but only one parent is allowed to have attributes ' - 'created by\n' - ' slots (the other bases must have empty slot layouts) - ' - 'violations\n' - ' raise "TypeError".\n' - '\n' - '\n' - 'Customizing class creation\n' - '==========================\n' - '\n' - 'Whenever a class inherits from another class, ' - '*__init_subclass__* is\n' - 'called on that class. This way, it is possible to write ' - 'classes which\n' - 'change the behavior of subclasses. This is closely related ' - 'to class\n' - 'decorators, but where class decorators only affect the ' - 'specific class\n' - 'they’re applied to, "__init_subclass__" solely applies to ' - 'future\n' - 'subclasses of the class defining the method.\n' - '\n' - 'classmethod object.__init_subclass__(cls)\n' - '\n' - ' This method is called whenever the containing class is ' - 'subclassed.\n' - ' *cls* is then the new subclass. If defined as a normal ' - 'instance\n' - ' method, this method is implicitly converted to a class ' - 'method.\n' - '\n' - ' Keyword arguments which are given to a new class are ' - 'passed to the\n' - ' parent’s class "__init_subclass__". For compatibility ' - 'with other\n' - ' classes using "__init_subclass__", one should take out ' - 'the needed\n' - ' keyword arguments and pass the others over to the base ' - 'class, as\n' - ' in:\n' - '\n' - ' class Philosopher:\n' - ' def __init_subclass__(cls, default_name, ' - '**kwargs):\n' - ' super().__init_subclass__(**kwargs)\n' - ' cls.default_name = default_name\n' - '\n' - ' class AustralianPhilosopher(Philosopher, ' - 'default_name="Bruce"):\n' - ' pass\n' - '\n' - ' The default implementation "object.__init_subclass__" ' - 'does nothing,\n' - ' but raises an error if it is called with any arguments.\n' - '\n' - ' Note: The metaclass hint "metaclass" is consumed by the ' - 'rest of\n' - ' the type machinery, and is never passed to ' - '"__init_subclass__"\n' - ' implementations. The actual metaclass (rather than the ' - 'explicit\n' - ' hint) can be accessed as "type(cls)".\n' - '\n' - ' New in version 3.6.\n' - '\n' - '\n' - 'Metaclasses\n' - '-----------\n' - '\n' - 'By default, classes are constructed using "type()". The ' - 'class body is\n' - 'executed in a new namespace and the class name is bound ' - 'locally to the\n' - 'result of "type(name, bases, namespace)".\n' - '\n' - 'The class creation process can be customized by passing the\n' - '"metaclass" keyword argument in the class definition line, ' - 'or by\n' - 'inheriting from an existing class that included such an ' - 'argument. In\n' - 'the following example, both "MyClass" and "MySubclass" are ' - 'instances\n' - 'of "Meta":\n' - '\n' - ' class Meta(type):\n' - ' pass\n' - '\n' - ' class MyClass(metaclass=Meta):\n' - ' pass\n' - '\n' - ' class MySubclass(MyClass):\n' - ' pass\n' - '\n' - 'Any other keyword arguments that are specified in the class ' - 'definition\n' - 'are passed through to all metaclass operations described ' - 'below.\n' - '\n' - 'When a class definition is executed, the following steps ' - 'occur:\n' - '\n' - '* the appropriate metaclass is determined\n' - '\n' - '* the class namespace is prepared\n' - '\n' - '* the class body is executed\n' - '\n' - '* the class object is created\n' - '\n' - '\n' - 'Determining the appropriate metaclass\n' - '-------------------------------------\n' - '\n' - 'The appropriate metaclass for a class definition is ' - 'determined as\n' - 'follows:\n' - '\n' - '* if no bases and no explicit metaclass are given, then ' - '"type()" is\n' - ' used\n' - '\n' - '* if an explicit metaclass is given and it is *not* an ' - 'instance of\n' - ' "type()", then it is used directly as the metaclass\n' - '\n' - '* if an instance of "type()" is given as the explicit ' - 'metaclass, or\n' - ' bases are defined, then the most derived metaclass is ' - 'used\n' - '\n' - 'The most derived metaclass is selected from the explicitly ' - 'specified\n' - 'metaclass (if any) and the metaclasses (i.e. "type(cls)") of ' - 'all\n' - 'specified base classes. The most derived metaclass is one ' - 'which is a\n' - 'subtype of *all* of these candidate metaclasses. If none of ' - 'the\n' - 'candidate metaclasses meets that criterion, then the class ' - 'definition\n' - 'will fail with "TypeError".\n' - '\n' - '\n' - 'Preparing the class namespace\n' - '-----------------------------\n' - '\n' - 'Once the appropriate metaclass has been identified, then the ' - 'class\n' - 'namespace is prepared. If the metaclass has a "__prepare__" ' - 'attribute,\n' - 'it is called as "namespace = metaclass.__prepare__(name, ' - 'bases,\n' - '**kwds)" (where the additional keyword arguments, if any, ' - 'come from\n' - 'the class definition).\n' - '\n' - 'If the metaclass has no "__prepare__" attribute, then the ' - 'class\n' - 'namespace is initialised as an empty ordered mapping.\n' - '\n' - 'See also:\n' - '\n' - ' **PEP 3115** - Metaclasses in Python 3000\n' - ' Introduced the "__prepare__" namespace hook\n' - '\n' - '\n' - 'Executing the class body\n' - '------------------------\n' - '\n' - 'The class body is executed (approximately) as "exec(body, ' - 'globals(),\n' - 'namespace)". The key difference from a normal call to ' - '"exec()" is that\n' - 'lexical scoping allows the class body (including any ' - 'methods) to\n' - 'reference names from the current and outer scopes when the ' - 'class\n' - 'definition occurs inside a function.\n' - '\n' - 'However, even when the class definition occurs inside the ' - 'function,\n' - 'methods defined inside the class still cannot see names ' - 'defined at the\n' - 'class scope. Class variables must be accessed through the ' - 'first\n' - 'parameter of instance or class methods, or through the ' - 'implicit\n' - 'lexically scoped "__class__" reference described in the next ' - 'section.\n' - '\n' - '\n' - 'Creating the class object\n' - '-------------------------\n' - '\n' - 'Once the class namespace has been populated by executing the ' - 'class\n' - 'body, the class object is created by calling ' - '"metaclass(name, bases,\n' - 'namespace, **kwds)" (the additional keywords passed here are ' - 'the same\n' - 'as those passed to "__prepare__").\n' - '\n' - 'This class object is the one that will be referenced by the ' - 'zero-\n' - 'argument form of "super()". "__class__" is an implicit ' - 'closure\n' - 'reference created by the compiler if any methods in a class ' - 'body refer\n' - 'to either "__class__" or "super". This allows the zero ' - 'argument form\n' - 'of "super()" to correctly identify the class being defined ' - 'based on\n' - 'lexical scoping, while the class or instance that was used ' - 'to make the\n' - 'current call is identified based on the first argument ' - 'passed to the\n' - 'method.\n' - '\n' - '**CPython implementation detail:** In CPython 3.6 and later, ' - 'the\n' - '"__class__" cell is passed to the metaclass as a ' - '"__classcell__" entry\n' - 'in the class namespace. If present, this must be propagated ' - 'up to the\n' - '"type.__new__" call in order for the class to be ' - 'initialised\n' - 'correctly. Failing to do so will result in a ' - '"DeprecationWarning" in\n' - 'Python 3.6, and a "RuntimeError" in Python 3.8.\n' - '\n' - 'When using the default metaclass "type", or any metaclass ' - 'that\n' - 'ultimately calls "type.__new__", the following additional\n' - 'customisation steps are invoked after creating the class ' - 'object:\n' - '\n' - '* first, "type.__new__" collects all of the descriptors in ' - 'the class\n' - ' namespace that define a "__set_name__()" method;\n' - '\n' - '* second, all of these "__set_name__" methods are called ' - 'with the\n' - ' class being defined and the assigned name of that ' - 'particular\n' - ' descriptor; and\n' - '\n' - '* finally, the "__init_subclass__()" hook is called on the ' - 'immediate\n' - ' parent of the new class in its method resolution order.\n' - '\n' - 'After the class object is created, it is passed to the ' - 'class\n' - 'decorators included in the class definition (if any) and the ' - 'resulting\n' - 'object is bound in the local namespace as the defined ' - 'class.\n' - '\n' - 'When a new class is created by "type.__new__", the object ' - 'provided as\n' - 'the namespace parameter is copied to a new ordered mapping ' - 'and the\n' - 'original object is discarded. The new copy is wrapped in a ' - 'read-only\n' - 'proxy, which becomes the "__dict__" attribute of the class ' - 'object.\n' - '\n' - 'See also:\n' - '\n' - ' **PEP 3135** - New super\n' - ' Describes the implicit "__class__" closure reference\n' - '\n' - '\n' - 'Uses for metaclasses\n' - '--------------------\n' - '\n' - 'The potential uses for metaclasses are boundless. Some ideas ' - 'that have\n' - 'been explored include enum, logging, interface checking, ' - 'automatic\n' - 'delegation, automatic property creation, proxies, ' - 'frameworks, and\n' - 'automatic resource locking/synchronization.\n' - '\n' - '\n' - 'Customizing instance and subclass checks\n' - '========================================\n' + ' same as if that method was called.\n', + 'class': 'Class definitions\n' + '*****************\n' + '\n' + 'A class definition defines a class object (see section The ' + 'standard\n' + 'type hierarchy):\n' + '\n' + ' classdef ::= [decorators] "class" classname [type_params] ' + '[inheritance] ":" suite\n' + ' inheritance ::= "(" [argument_list] ")"\n' + ' classname ::= identifier\n' + '\n' + 'A class definition is an executable statement. The inheritance ' + 'list\n' + 'usually gives a list of base classes (see Metaclasses for more\n' + 'advanced uses), so each item in the list should evaluate to a ' + 'class\n' + 'object which allows subclassing. Classes without an inheritance ' + 'list\n' + 'inherit, by default, from the base class "object"; hence,\n' + '\n' + ' class Foo:\n' + ' pass\n' + '\n' + 'is equivalent to\n' + '\n' + ' class Foo(object):\n' + ' pass\n' + '\n' + 'The class’s suite is then executed in a new execution frame (see\n' + 'Naming and binding), using a newly created local namespace and the\n' + 'original global namespace. (Usually, the suite contains mostly\n' + 'function definitions.) When the class’s suite finishes execution, ' + 'its\n' + 'execution frame is discarded but its local namespace is saved. [5] ' + 'A\n' + 'class object is then created using the inheritance list for the ' + 'base\n' + 'classes and the saved local namespace for the attribute ' + 'dictionary.\n' + 'The class name is bound to this class object in the original local\n' + 'namespace.\n' + '\n' + 'The order in which attributes are defined in the class body is\n' + 'preserved in the new class’s "__dict__". Note that this is ' + 'reliable\n' + 'only right after the class is created and only for classes that ' + 'were\n' + 'defined using the definition syntax.\n' + '\n' + 'Class creation can be customized heavily using metaclasses.\n' + '\n' + 'Classes can also be decorated: just like when decorating ' + 'functions,\n' + '\n' + ' @f1(arg)\n' + ' @f2\n' + ' class Foo: pass\n' + '\n' + 'is roughly equivalent to\n' + '\n' + ' class Foo: pass\n' + ' Foo = f1(arg)(f2(Foo))\n' + '\n' + 'The evaluation rules for the decorator expressions are the same as ' + 'for\n' + 'function decorators. The result is then bound to the class name.\n' + '\n' + 'Changed in version 3.9: Classes may be decorated with any valid\n' + '"assignment_expression". Previously, the grammar was much more\n' + 'restrictive; see **PEP 614** for details.\n' + '\n' + 'A list of type parameters may be given in square brackets ' + 'immediately\n' + 'after the class’s name. This indicates to static type checkers ' + 'that\n' + 'the class is generic. At runtime, the type parameters can be ' + 'retrieved\n' + 'from the class’s "__type_params__" attribute. See Generic classes ' + 'for\n' + 'more.\n' + '\n' + 'Changed in version 3.12: Type parameter lists are new in Python ' + '3.12.\n' + '\n' + '**Programmer’s note:** Variables defined in the class definition ' + 'are\n' + 'class attributes; they are shared by instances. Instance ' + 'attributes\n' + 'can be set in a method with "self.name = value". Both class and\n' + 'instance attributes are accessible through the notation ' + '“"self.name"”,\n' + 'and an instance attribute hides a class attribute with the same ' + 'name\n' + 'when accessed in this way. Class attributes can be used as ' + 'defaults\n' + 'for instance attributes, but using mutable values there can lead ' + 'to\n' + 'unexpected results. Descriptors can be used to create instance\n' + 'variables with different implementation details.\n' + '\n' + 'See also:\n' + '\n' + ' **PEP 3115** - Metaclasses in Python 3000\n' + ' The proposal that changed the declaration of metaclasses to ' + 'the\n' + ' current syntax, and the semantics for how classes with\n' + ' metaclasses are constructed.\n' + '\n' + ' **PEP 3129** - Class Decorators\n' + ' The proposal that added class decorators. Function and ' + 'method\n' + ' decorators were introduced in **PEP 318**.\n', + 'comparisons': 'Comparisons\n' + '***********\n' + '\n' + 'Unlike C, all comparison operations in Python have the same ' + 'priority,\n' + 'which is lower than that of any arithmetic, shifting or ' + 'bitwise\n' + 'operation. Also unlike C, expressions like "a < b < c" have ' + 'the\n' + 'interpretation that is conventional in mathematics:\n' + '\n' + ' comparison ::= or_expr (comp_operator or_expr)*\n' + ' comp_operator ::= "<" | ">" | "==" | ">=" | "<=" | "!="\n' + ' | "is" ["not"] | ["not"] "in"\n' + '\n' + 'Comparisons yield boolean values: "True" or "False". Custom ' + '*rich\n' + 'comparison methods* may return non-boolean values. In this ' + 'case Python\n' + 'will call "bool()" on such value in boolean contexts.\n' + '\n' + 'Comparisons can be chained arbitrarily, e.g., "x < y <= z" ' + 'is\n' + 'equivalent to "x < y and y <= z", except that "y" is ' + 'evaluated only\n' + 'once (but in both cases "z" is not evaluated at all when "x < ' + 'y" is\n' + 'found to be false).\n' + '\n' + 'Formally, if *a*, *b*, *c*, …, *y*, *z* are expressions and ' + '*op1*,\n' + '*op2*, …, *opN* are comparison operators, then "a op1 b op2 c ' + '... y\n' + 'opN z" is equivalent to "a op1 b and b op2 c and ... y opN ' + 'z", except\n' + 'that each expression is evaluated at most once.\n' + '\n' + 'Note that "a op1 b op2 c" doesn’t imply any kind of ' + 'comparison between\n' + '*a* and *c*, so that, e.g., "x < y > z" is perfectly legal ' + '(though\n' + 'perhaps not pretty).\n' + '\n' + '\n' + 'Value comparisons\n' + '=================\n' + '\n' + 'The operators "<", ">", "==", ">=", "<=", and "!=" compare ' + 'the values\n' + 'of two objects. The objects do not need to have the same ' + 'type.\n' + '\n' + 'Chapter Objects, values and types states that objects have a ' + 'value (in\n' + 'addition to type and identity). The value of an object is a ' + 'rather\n' + 'abstract notion in Python: For example, there is no canonical ' + 'access\n' + 'method for an object’s value. Also, there is no requirement ' + 'that the\n' + 'value of an object should be constructed in a particular way, ' + 'e.g.\n' + 'comprised of all its data attributes. Comparison operators ' + 'implement a\n' + 'particular notion of what the value of an object is. One can ' + 'think of\n' + 'them as defining the value of an object indirectly, by means ' + 'of their\n' + 'comparison implementation.\n' + '\n' + 'Because all types are (direct or indirect) subtypes of ' + '"object", they\n' + 'inherit the default comparison behavior from "object". Types ' + 'can\n' + 'customize their comparison behavior by implementing *rich ' + 'comparison\n' + 'methods* like "__lt__()", described in Basic customization.\n' + '\n' + 'The default behavior for equality comparison ("==" and "!=") ' + 'is based\n' + 'on the identity of the objects. Hence, equality comparison ' + 'of\n' + 'instances with the same identity results in equality, and ' + 'equality\n' + 'comparison of instances with different identities results in\n' + 'inequality. A motivation for this default behavior is the ' + 'desire that\n' + 'all objects should be reflexive (i.e. "x is y" implies "x == ' + 'y").\n' + '\n' + 'A default order comparison ("<", ">", "<=", and ">=") is not ' + 'provided;\n' + 'an attempt raises "TypeError". A motivation for this default ' + 'behavior\n' + 'is the lack of a similar invariant as for equality.\n' + '\n' + 'The behavior of the default equality comparison, that ' + 'instances with\n' + 'different identities are always unequal, may be in contrast ' + 'to what\n' + 'types will need that have a sensible definition of object ' + 'value and\n' + 'value-based equality. Such types will need to customize ' + 'their\n' + 'comparison behavior, and in fact, a number of built-in types ' + 'have done\n' + 'that.\n' + '\n' + 'The following list describes the comparison behavior of the ' + 'most\n' + 'important built-in types.\n' + '\n' + '* Numbers of built-in numeric types (Numeric Types — int, ' + 'float,\n' + ' complex) and of the standard library types ' + '"fractions.Fraction" and\n' + ' "decimal.Decimal" can be compared within and across their ' + 'types,\n' + ' with the restriction that complex numbers do not support ' + 'order\n' + ' comparison. Within the limits of the types involved, they ' + 'compare\n' + ' mathematically (algorithmically) correct without loss of ' + 'precision.\n' + '\n' + ' The not-a-number values "float(\'NaN\')" and ' + '"decimal.Decimal(\'NaN\')"\n' + ' are special. Any ordered comparison of a number to a ' + 'not-a-number\n' + ' value is false. A counter-intuitive implication is that ' + 'not-a-number\n' + ' values are not equal to themselves. For example, if "x =\n' + ' float(\'NaN\')", "3 < x", "x < 3" and "x == x" are all ' + 'false, while "x\n' + ' != x" is true. This behavior is compliant with IEEE 754.\n' + '\n' + '* "None" and "NotImplemented" are singletons. **PEP 8** ' + 'advises that\n' + ' comparisons for singletons should always be done with "is" ' + 'or "is\n' + ' not", never the equality operators.\n' + '\n' + '* Binary sequences (instances of "bytes" or "bytearray") can ' + 'be\n' + ' compared within and across their types. They compare\n' + ' lexicographically using the numeric values of their ' + 'elements.\n' + '\n' + '* Strings (instances of "str") compare lexicographically ' + 'using the\n' + ' numerical Unicode code points (the result of the built-in ' + 'function\n' + ' "ord()") of their characters. [3]\n' + '\n' + ' Strings and binary sequences cannot be directly compared.\n' + '\n' + '* Sequences (instances of "tuple", "list", or "range") can be ' + 'compared\n' + ' only within each of their types, with the restriction that ' + 'ranges do\n' + ' not support order comparison. Equality comparison across ' + 'these\n' + ' types results in inequality, and ordering comparison across ' + 'these\n' + ' types raises "TypeError".\n' + '\n' + ' Sequences compare lexicographically using comparison of\n' + ' corresponding elements. The built-in containers typically ' + 'assume\n' + ' identical objects are equal to themselves. That lets them ' + 'bypass\n' + ' equality tests for identical objects to improve performance ' + 'and to\n' + ' maintain their internal invariants.\n' + '\n' + ' Lexicographical comparison between built-in collections ' + 'works as\n' + ' follows:\n' + '\n' + ' * For two collections to compare equal, they must be of the ' + 'same\n' + ' type, have the same length, and each pair of ' + 'corresponding\n' + ' elements must compare equal (for example, "[1,2] == ' + '(1,2)" is\n' + ' false because the type is not the same).\n' + '\n' + ' * Collections that support order comparison are ordered the ' + 'same as\n' + ' their first unequal elements (for example, "[1,2,x] <= ' + '[1,2,y]"\n' + ' has the same value as "x <= y"). If a corresponding ' + 'element does\n' + ' not exist, the shorter collection is ordered first (for ' + 'example,\n' + ' "[1,2] < [1,2,3]" is true).\n' + '\n' + '* Mappings (instances of "dict") compare equal if and only if ' + 'they\n' + ' have equal "(key, value)" pairs. Equality comparison of the ' + 'keys and\n' + ' values enforces reflexivity.\n' + '\n' + ' Order comparisons ("<", ">", "<=", and ">=") raise ' + '"TypeError".\n' + '\n' + '* Sets (instances of "set" or "frozenset") can be compared ' + 'within and\n' + ' across their types.\n' + '\n' + ' They define order comparison operators to mean subset and ' + 'superset\n' + ' tests. Those relations do not define total orderings (for ' + 'example,\n' + ' the two sets "{1,2}" and "{2,3}" are not equal, nor subsets ' + 'of one\n' + ' another, nor supersets of one another). Accordingly, sets ' + 'are not\n' + ' appropriate arguments for functions which depend on total ' + 'ordering\n' + ' (for example, "min()", "max()", and "sorted()" produce ' + 'undefined\n' + ' results given a list of sets as inputs).\n' + '\n' + ' Comparison of sets enforces reflexivity of its elements.\n' + '\n' + '* Most other built-in types have no comparison methods ' + 'implemented, so\n' + ' they inherit the default comparison behavior.\n' + '\n' + 'User-defined classes that customize their comparison behavior ' + 'should\n' + 'follow some consistency rules, if possible:\n' + '\n' + '* Equality comparison should be reflexive. In other words, ' + 'identical\n' + ' objects should compare equal:\n' + '\n' + ' "x is y" implies "x == y"\n' + '\n' + '* Comparison should be symmetric. In other words, the ' + 'following\n' + ' expressions should have the same result:\n' + '\n' + ' "x == y" and "y == x"\n' + '\n' + ' "x != y" and "y != x"\n' + '\n' + ' "x < y" and "y > x"\n' + '\n' + ' "x <= y" and "y >= x"\n' + '\n' + '* Comparison should be transitive. The following ' + '(non-exhaustive)\n' + ' examples illustrate that:\n' + '\n' + ' "x > y and y > z" implies "x > z"\n' + '\n' + ' "x < y and y <= z" implies "x < z"\n' + '\n' + '* Inverse comparison should result in the boolean negation. ' + 'In other\n' + ' words, the following expressions should have the same ' + 'result:\n' + '\n' + ' "x == y" and "not x != y"\n' + '\n' + ' "x < y" and "not x >= y" (for total ordering)\n' + '\n' + ' "x > y" and "not x <= y" (for total ordering)\n' + '\n' + ' The last two expressions apply to totally ordered ' + 'collections (e.g.\n' + ' to sequences, but not to sets or mappings). See also the\n' + ' "total_ordering()" decorator.\n' + '\n' + '* The "hash()" result should be consistent with equality. ' + 'Objects that\n' + ' are equal should either have the same hash value, or be ' + 'marked as\n' + ' unhashable.\n' + '\n' + 'Python does not enforce these consistency rules. In fact, ' + 'the\n' + 'not-a-number values are an example for not following these ' + 'rules.\n' + '\n' + '\n' + 'Membership test operations\n' + '==========================\n' + '\n' + 'The operators "in" and "not in" test for membership. "x in ' + 's"\n' + 'evaluates to "True" if *x* is a member of *s*, and "False" ' + 'otherwise.\n' + '"x not in s" returns the negation of "x in s". All built-in ' + 'sequences\n' + 'and set types support this as well as dictionary, for which ' + '"in" tests\n' + 'whether the dictionary has a given key. For container types ' + 'such as\n' + 'list, tuple, set, frozenset, dict, or collections.deque, the\n' + 'expression "x in y" is equivalent to "any(x is e or x == e ' + 'for e in\n' + 'y)".\n' + '\n' + 'For the string and bytes types, "x in y" is "True" if and ' + 'only if *x*\n' + 'is a substring of *y*. An equivalent test is "y.find(x) != ' + '-1".\n' + 'Empty strings are always considered to be a substring of any ' + 'other\n' + 'string, so """ in "abc"" will return "True".\n' + '\n' + 'For user-defined classes which define the "__contains__()" ' + 'method, "x\n' + 'in y" returns "True" if "y.__contains__(x)" returns a true ' + 'value, and\n' + '"False" otherwise.\n' + '\n' + 'For user-defined classes which do not define "__contains__()" ' + 'but do\n' + 'define "__iter__()", "x in y" is "True" if some value "z", ' + 'for which\n' + 'the expression "x is z or x == z" is true, is produced while ' + 'iterating\n' + 'over "y". If an exception is raised during the iteration, it ' + 'is as if\n' + '"in" raised that exception.\n' + '\n' + 'Lastly, the old-style iteration protocol is tried: if a class ' + 'defines\n' + '"__getitem__()", "x in y" is "True" if and only if there is a ' + 'non-\n' + 'negative integer index *i* such that "x is y[i] or x == ' + 'y[i]", and no\n' + 'lower integer index raises the "IndexError" exception. (If ' + 'any other\n' + 'exception is raised, it is as if "in" raised that ' + 'exception).\n' + '\n' + 'The operator "not in" is defined to have the inverse truth ' + 'value of\n' + '"in".\n' + '\n' + '\n' + 'Identity comparisons\n' + '====================\n' + '\n' + 'The operators "is" and "is not" test for an object’s ' + 'identity: "x is\n' + 'y" is true if and only if *x* and *y* are the same object. ' + 'An\n' + 'Object’s identity is determined using the "id()" function. ' + '"x is not\n' + 'y" yields the inverse truth value. [4]\n', + 'compound': 'Compound statements\n' + '*******************\n' + '\n' + 'Compound statements contain (groups of) other statements; they ' + 'affect\n' + 'or control the execution of those other statements in some way. ' + 'In\n' + 'general, compound statements span multiple lines, although in ' + 'simple\n' + 'incarnations a whole compound statement may be contained in one ' + 'line.\n' + '\n' + 'The "if", "while" and "for" statements implement traditional ' + 'control\n' + 'flow constructs. "try" specifies exception handlers and/or ' + 'cleanup\n' + 'code for a group of statements, while the "with" statement ' + 'allows the\n' + 'execution of initialization and finalization code around a block ' + 'of\n' + 'code. Function and class definitions are also syntactically ' + 'compound\n' + 'statements.\n' + '\n' + 'A compound statement consists of one or more ‘clauses.’ A ' + 'clause\n' + 'consists of a header and a ‘suite.’ The clause headers of a\n' + 'particular compound statement are all at the same indentation ' + 'level.\n' + 'Each clause header begins with a uniquely identifying keyword ' + 'and ends\n' + 'with a colon. A suite is a group of statements controlled by a\n' + 'clause. A suite can be one or more semicolon-separated simple\n' + 'statements on the same line as the header, following the ' + 'header’s\n' + 'colon, or it can be one or more indented statements on ' + 'subsequent\n' + 'lines. Only the latter form of a suite can contain nested ' + 'compound\n' + 'statements; the following is illegal, mostly because it wouldn’t ' + 'be\n' + 'clear to which "if" clause a following "else" clause would ' + 'belong:\n' + '\n' + ' if test1: if test2: print(x)\n' + '\n' + 'Also note that the semicolon binds tighter than the colon in ' + 'this\n' + 'context, so that in the following example, either all or none of ' + 'the\n' + '"print()" calls are executed:\n' + '\n' + ' if x < y < z: print(x); print(y); print(z)\n' + '\n' + 'Summarizing:\n' + '\n' + ' compound_stmt ::= if_stmt\n' + ' | while_stmt\n' + ' | for_stmt\n' + ' | try_stmt\n' + ' | with_stmt\n' + ' | match_stmt\n' + ' | funcdef\n' + ' | classdef\n' + ' | async_with_stmt\n' + ' | async_for_stmt\n' + ' | async_funcdef\n' + ' suite ::= stmt_list NEWLINE | NEWLINE INDENT ' + 'statement+ DEDENT\n' + ' statement ::= stmt_list NEWLINE | compound_stmt\n' + ' stmt_list ::= simple_stmt (";" simple_stmt)* [";"]\n' + '\n' + 'Note that statements always end in a "NEWLINE" possibly followed ' + 'by a\n' + '"DEDENT". Also note that optional continuation clauses always ' + 'begin\n' + 'with a keyword that cannot start a statement, thus there are no\n' + 'ambiguities (the ‘dangling "else"’ problem is solved in Python ' + 'by\n' + 'requiring nested "if" statements to be indented).\n' + '\n' + 'The formatting of the grammar rules in the following sections ' + 'places\n' + 'each clause on a separate line for clarity.\n' + '\n' + '\n' + 'The "if" statement\n' + '==================\n' + '\n' + 'The "if" statement is used for conditional execution:\n' + '\n' + ' if_stmt ::= "if" assignment_expression ":" suite\n' + ' ("elif" assignment_expression ":" suite)*\n' + ' ["else" ":" suite]\n' + '\n' + 'It selects exactly one of the suites by evaluating the ' + 'expressions one\n' + 'by one until one is found to be true (see section Boolean ' + 'operations\n' + 'for the definition of true and false); then that suite is ' + 'executed\n' + '(and no other part of the "if" statement is executed or ' + 'evaluated).\n' + 'If all expressions are false, the suite of the "else" clause, ' + 'if\n' + 'present, is executed.\n' + '\n' + '\n' + 'The "while" statement\n' + '=====================\n' + '\n' + 'The "while" statement is used for repeated execution as long as ' + 'an\n' + 'expression is true:\n' + '\n' + ' while_stmt ::= "while" assignment_expression ":" suite\n' + ' ["else" ":" suite]\n' + '\n' + 'This repeatedly tests the expression and, if it is true, ' + 'executes the\n' + 'first suite; if the expression is false (which may be the first ' + 'time\n' + 'it is tested) the suite of the "else" clause, if present, is ' + 'executed\n' + 'and the loop terminates.\n' + '\n' + 'A "break" statement executed in the first suite terminates the ' + 'loop\n' + 'without executing the "else" clause’s suite. A "continue" ' + 'statement\n' + 'executed in the first suite skips the rest of the suite and goes ' + 'back\n' + 'to testing the expression.\n' + '\n' + '\n' + 'The "for" statement\n' + '===================\n' + '\n' + 'The "for" statement is used to iterate over the elements of a ' + 'sequence\n' + '(such as a string, tuple or list) or other iterable object:\n' + '\n' + ' for_stmt ::= "for" target_list "in" starred_list ":" suite\n' + ' ["else" ":" suite]\n' + '\n' + 'The "starred_list" expression is evaluated once; it should yield ' + 'an\n' + '*iterable* object. An *iterator* is created for that iterable. ' + 'The\n' + 'first item provided by the iterator is then assigned to the ' + 'target\n' + 'list using the standard rules for assignments (see Assignment\n' + 'statements), and the suite is executed. This repeats for each ' + 'item\n' + 'provided by the iterator. When the iterator is exhausted, the ' + 'suite\n' + 'in the "else" clause, if present, is executed, and the loop\n' + 'terminates.\n' + '\n' + 'A "break" statement executed in the first suite terminates the ' + 'loop\n' + 'without executing the "else" clause’s suite. A "continue" ' + 'statement\n' + 'executed in the first suite skips the rest of the suite and ' + 'continues\n' + 'with the next item, or with the "else" clause if there is no ' + 'next\n' + 'item.\n' + '\n' + 'The for-loop makes assignments to the variables in the target ' + 'list.\n' + 'This overwrites all previous assignments to those variables ' + 'including\n' + 'those made in the suite of the for-loop:\n' + '\n' + ' for i in range(10):\n' + ' print(i)\n' + ' i = 5 # this will not affect the for-loop\n' + ' # because i will be overwritten with ' + 'the next\n' + ' # index in the range\n' + '\n' + 'Names in the target list are not deleted when the loop is ' + 'finished,\n' + 'but if the sequence is empty, they will not have been assigned ' + 'to at\n' + 'all by the loop. Hint: the built-in type "range()" represents\n' + 'immutable arithmetic sequences of integers. For instance, ' + 'iterating\n' + '"range(3)" successively yields 0, 1, and then 2.\n' + '\n' + 'Changed in version 3.11: Starred elements are now allowed in ' + 'the\n' + 'expression list.\n' + '\n' + '\n' + 'The "try" statement\n' + '===================\n' + '\n' + 'The "try" statement specifies exception handlers and/or cleanup ' + 'code\n' + 'for a group of statements:\n' + '\n' + ' try_stmt ::= try1_stmt | try2_stmt | try3_stmt\n' + ' try1_stmt ::= "try" ":" suite\n' + ' ("except" [expression ["as" identifier]] ":" ' + 'suite)+\n' + ' ["else" ":" suite]\n' + ' ["finally" ":" suite]\n' + ' try2_stmt ::= "try" ":" suite\n' + ' ("except" "*" expression ["as" identifier] ":" ' + 'suite)+\n' + ' ["else" ":" suite]\n' + ' ["finally" ":" suite]\n' + ' try3_stmt ::= "try" ":" suite\n' + ' "finally" ":" suite\n' + '\n' + 'Additional information on exceptions can be found in section\n' + 'Exceptions, and information on using the "raise" statement to ' + 'generate\n' + 'exceptions may be found in section The raise statement.\n' + '\n' + '\n' + '"except" clause\n' + '---------------\n' + '\n' + 'The "except" clause(s) specify one or more exception handlers. ' + 'When no\n' + 'exception occurs in the "try" clause, no exception handler is\n' + 'executed. When an exception occurs in the "try" suite, a search ' + 'for an\n' + 'exception handler is started. This search inspects the "except"\n' + 'clauses in turn until one is found that matches the exception. ' + 'An\n' + 'expression-less "except" clause, if present, must be last; it ' + 'matches\n' + 'any exception.\n' + '\n' + 'For an "except" clause with an expression, the expression must\n' + 'evaluate to an exception type or a tuple of exception types. ' + 'The\n' + 'raised exception matches an "except" clause whose expression ' + 'evaluates\n' + 'to the class or a *non-virtual base class* of the exception ' + 'object, or\n' + 'to a tuple that contains such a class.\n' + '\n' + 'If no "except" clause matches the exception, the search for an\n' + 'exception handler continues in the surrounding code and on the\n' + 'invocation stack. [1]\n' + '\n' + 'If the evaluation of an expression in the header of an "except" ' + 'clause\n' + 'raises an exception, the original search for a handler is ' + 'canceled and\n' + 'a search starts for the new exception in the surrounding code ' + 'and on\n' + 'the call stack (it is treated as if the entire "try" statement ' + 'raised\n' + 'the exception).\n' + '\n' + 'When a matching "except" clause is found, the exception is ' + 'assigned to\n' + 'the target specified after the "as" keyword in that "except" ' + 'clause,\n' + 'if present, and the "except" clause’s suite is executed. All ' + '"except"\n' + 'clauses must have an executable block. When the end of this ' + 'block is\n' + 'reached, execution continues normally after the entire "try"\n' + 'statement. (This means that if two nested handlers exist for the ' + 'same\n' + 'exception, and the exception occurs in the "try" clause of the ' + 'inner\n' + 'handler, the outer handler will not handle the exception.)\n' + '\n' + 'When an exception has been assigned using "as target", it is ' + 'cleared\n' + 'at the end of the "except" clause. This is as if\n' + '\n' + ' except E as N:\n' + ' foo\n' + '\n' + 'was translated to\n' + '\n' + ' except E as N:\n' + ' try:\n' + ' foo\n' + ' finally:\n' + ' del N\n' + '\n' + 'This means the exception must be assigned to a different name to ' + 'be\n' + 'able to refer to it after the "except" clause. Exceptions are ' + 'cleared\n' + 'because with the traceback attached to them, they form a ' + 'reference\n' + 'cycle with the stack frame, keeping all locals in that frame ' + 'alive\n' + 'until the next garbage collection occurs.\n' + '\n' + 'Before an "except" clause’s suite is executed, the exception is ' + 'stored\n' + 'in the "sys" module, where it can be accessed from within the ' + 'body of\n' + 'the "except" clause by calling "sys.exception()". When leaving ' + 'an\n' + 'exception handler, the exception stored in the "sys" module is ' + 'reset\n' + 'to its previous value:\n' + '\n' + ' >>> print(sys.exception())\n' + ' None\n' + ' >>> try:\n' + ' ... raise TypeError\n' + ' ... except:\n' + ' ... print(repr(sys.exception()))\n' + ' ... try:\n' + ' ... raise ValueError\n' + ' ... except:\n' + ' ... print(repr(sys.exception()))\n' + ' ... print(repr(sys.exception()))\n' + ' ...\n' + ' TypeError()\n' + ' ValueError()\n' + ' TypeError()\n' + ' >>> print(sys.exception())\n' + ' None\n' + '\n' + '\n' + '"except*" clause\n' + '----------------\n' + '\n' + 'The "except*" clause(s) are used for handling "ExceptionGroup"s. ' + 'The\n' + 'exception type for matching is interpreted as in the case of ' + '"except",\n' + 'but in the case of exception groups we can have partial matches ' + 'when\n' + 'the type matches some of the exceptions in the group. This means ' + 'that\n' + 'multiple "except*" clauses can execute, each handling part of ' + 'the\n' + 'exception group. Each clause executes at most once and handles ' + 'an\n' + 'exception group of all matching exceptions. Each exception in ' + 'the\n' + 'group is handled by at most one "except*" clause, the first ' + 'that\n' + 'matches it.\n' + '\n' + ' >>> try:\n' + ' ... raise ExceptionGroup("eg",\n' + ' ... [ValueError(1), TypeError(2), OSError(3), ' + 'OSError(4)])\n' + ' ... except* TypeError as e:\n' + " ... print(f'caught {type(e)} with nested " + "{e.exceptions}')\n" + ' ... except* OSError as e:\n' + " ... print(f'caught {type(e)} with nested " + "{e.exceptions}')\n" + ' ...\n' + " caught with nested (TypeError(2),)\n" + " caught with nested (OSError(3), " + 'OSError(4))\n' + ' + Exception Group Traceback (most recent call last):\n' + ' | File "", line 2, in \n' + ' | ExceptionGroup: eg\n' + ' +-+---------------- 1 ----------------\n' + ' | ValueError: 1\n' + ' +------------------------------------\n' + '\n' + 'Any remaining exceptions that were not handled by any "except*" ' + 'clause\n' + 'are re-raised at the end, along with all exceptions that were ' + 'raised\n' + 'from within the "except*" clauses. If this list contains more ' + 'than one\n' + 'exception to reraise, they are combined into an exception ' + 'group.\n' + '\n' + 'If the raised exception is not an exception group and its type ' + 'matches\n' + 'one of the "except*" clauses, it is caught and wrapped by an ' + 'exception\n' + 'group with an empty message string.\n' + '\n' + ' >>> try:\n' + ' ... raise BlockingIOError\n' + ' ... except* BlockingIOError as e:\n' + ' ... print(repr(e))\n' + ' ...\n' + " ExceptionGroup('', (BlockingIOError()))\n" + '\n' + 'An "except*" clause must have a matching expression; it cannot ' + 'be\n' + '"except*:". Furthermore, this expression cannot contain ' + 'exception\n' + 'group types, because that would have ambiguous semantics.\n' + '\n' + 'It is not possible to mix "except" and "except*" in the same ' + '"try".\n' + '"break", "continue" and "return" cannot appear in an "except*" ' + 'clause.\n' + '\n' + '\n' + '"else" clause\n' + '-------------\n' + '\n' + 'The optional "else" clause is executed if the control flow ' + 'leaves the\n' + '"try" suite, no exception was raised, and no "return", ' + '"continue", or\n' + '"break" statement was executed. Exceptions in the "else" clause ' + 'are\n' + 'not handled by the preceding "except" clauses.\n' + '\n' + '\n' + '"finally" clause\n' + '----------------\n' + '\n' + 'If "finally" is present, it specifies a ‘cleanup’ handler. The ' + '"try"\n' + 'clause is executed, including any "except" and "else" clauses. ' + 'If an\n' + 'exception occurs in any of the clauses and is not handled, the\n' + 'exception is temporarily saved. The "finally" clause is ' + 'executed. If\n' + 'there is a saved exception it is re-raised at the end of the ' + '"finally"\n' + 'clause. If the "finally" clause raises another exception, the ' + 'saved\n' + 'exception is set as the context of the new exception. If the ' + '"finally"\n' + 'clause executes a "return", "break" or "continue" statement, the ' + 'saved\n' + 'exception is discarded:\n' + '\n' + ' >>> def f():\n' + ' ... try:\n' + ' ... 1/0\n' + ' ... finally:\n' + ' ... return 42\n' + ' ...\n' + ' >>> f()\n' + ' 42\n' + '\n' + 'The exception information is not available to the program ' + 'during\n' + 'execution of the "finally" clause.\n' + '\n' + 'When a "return", "break" or "continue" statement is executed in ' + 'the\n' + '"try" suite of a "try"…"finally" statement, the "finally" clause ' + 'is\n' + 'also executed ‘on the way out.’\n' + '\n' + 'The return value of a function is determined by the last ' + '"return"\n' + 'statement executed. Since the "finally" clause always executes, ' + 'a\n' + '"return" statement executed in the "finally" clause will always ' + 'be the\n' + 'last one executed:\n' + '\n' + ' >>> def foo():\n' + ' ... try:\n' + " ... return 'try'\n" + ' ... finally:\n' + " ... return 'finally'\n" + ' ...\n' + ' >>> foo()\n' + " 'finally'\n" + '\n' + 'Changed in version 3.8: Prior to Python 3.8, a "continue" ' + 'statement\n' + 'was illegal in the "finally" clause due to a problem with the\n' + 'implementation.\n' + '\n' + '\n' + 'The "with" statement\n' + '====================\n' + '\n' + 'The "with" statement is used to wrap the execution of a block ' + 'with\n' + 'methods defined by a context manager (see section With ' + 'Statement\n' + 'Context Managers). This allows common "try"…"except"…"finally" ' + 'usage\n' + 'patterns to be encapsulated for convenient reuse.\n' + '\n' + ' with_stmt ::= "with" ( "(" with_stmt_contents ","? ' + '")" | with_stmt_contents ) ":" suite\n' + ' with_stmt_contents ::= with_item ("," with_item)*\n' + ' with_item ::= expression ["as" target]\n' + '\n' + 'The execution of the "with" statement with one “item” proceeds ' + 'as\n' + 'follows:\n' + '\n' + '1. The context expression (the expression given in the ' + '"with_item") is\n' + ' evaluated to obtain a context manager.\n' + '\n' + '2. The context manager’s "__enter__()" is loaded for later use.\n' + '\n' + '3. The context manager’s "__exit__()" is loaded for later use.\n' + '\n' + '4. The context manager’s "__enter__()" method is invoked.\n' + '\n' + '5. If a target was included in the "with" statement, the return ' + 'value\n' + ' from "__enter__()" is assigned to it.\n' + '\n' + ' Note:\n' + '\n' + ' The "with" statement guarantees that if the "__enter__()" ' + 'method\n' + ' returns without an error, then "__exit__()" will always be\n' + ' called. Thus, if an error occurs during the assignment to ' + 'the\n' + ' target list, it will be treated the same as an error ' + 'occurring\n' + ' within the suite would be. See step 7 below.\n' + '\n' + '6. The suite is executed.\n' + '\n' + '7. The context manager’s "__exit__()" method is invoked. If an\n' + ' exception caused the suite to be exited, its type, value, ' + 'and\n' + ' traceback are passed as arguments to "__exit__()". Otherwise, ' + 'three\n' + ' "None" arguments are supplied.\n' + '\n' + ' If the suite was exited due to an exception, and the return ' + 'value\n' + ' from the "__exit__()" method was false, the exception is ' + 'reraised.\n' + ' If the return value was true, the exception is suppressed, ' + 'and\n' + ' execution continues with the statement following the "with"\n' + ' statement.\n' + '\n' + ' If the suite was exited for any reason other than an ' + 'exception, the\n' + ' return value from "__exit__()" is ignored, and execution ' + 'proceeds\n' + ' at the normal location for the kind of exit that was taken.\n' + '\n' + 'The following code:\n' + '\n' + ' with EXPRESSION as TARGET:\n' + ' SUITE\n' + '\n' + 'is semantically equivalent to:\n' + '\n' + ' manager = (EXPRESSION)\n' + ' enter = type(manager).__enter__\n' + ' exit = type(manager).__exit__\n' + ' value = enter(manager)\n' + '\n' + ' try:\n' + ' TARGET = value\n' + ' SUITE\n' + ' except:\n' + ' if not exit(manager, *sys.exc_info()):\n' + ' raise\n' + ' else:\n' + ' exit(manager, None, None, None)\n' + '\n' + 'With more than one item, the context managers are processed as ' + 'if\n' + 'multiple "with" statements were nested:\n' + '\n' + ' with A() as a, B() as b:\n' + ' SUITE\n' + '\n' + 'is semantically equivalent to:\n' + '\n' + ' with A() as a:\n' + ' with B() as b:\n' + ' SUITE\n' + '\n' + 'You can also write multi-item context managers in multiple lines ' + 'if\n' + 'the items are surrounded by parentheses. For example:\n' + '\n' + ' with (\n' + ' A() as a,\n' + ' B() as b,\n' + ' ):\n' + ' SUITE\n' + '\n' + 'Changed in version 3.1: Support for multiple context ' + 'expressions.\n' + '\n' + 'Changed in version 3.10: Support for using grouping parentheses ' + 'to\n' + 'break the statement in multiple lines.\n' + '\n' + 'See also:\n' + '\n' + ' **PEP 343** - The “with” statement\n' + ' The specification, background, and examples for the Python ' + '"with"\n' + ' statement.\n' + '\n' + '\n' + 'The "match" statement\n' + '=====================\n' + '\n' + 'Added in version 3.10.\n' + '\n' + 'The match statement is used for pattern matching. Syntax:\n' + '\n' + ' match_stmt ::= \'match\' subject_expr ":" NEWLINE INDENT ' + 'case_block+ DEDENT\n' + ' subject_expr ::= star_named_expression "," ' + 'star_named_expressions?\n' + ' | named_expression\n' + ' case_block ::= \'case\' patterns [guard] ":" block\n' + '\n' + 'Note:\n' + '\n' + ' This section uses single quotes to denote soft keywords.\n' + '\n' + 'Pattern matching takes a pattern as input (following "case") and ' + 'a\n' + 'subject value (following "match"). The pattern (which may ' + 'contain\n' + 'subpatterns) is matched against the subject value. The outcomes ' + 'are:\n' + '\n' + '* A match success or failure (also termed a pattern success or\n' + ' failure).\n' + '\n' + '* Possible binding of matched values to a name. The ' + 'prerequisites for\n' + ' this are further discussed below.\n' + '\n' + 'The "match" and "case" keywords are soft keywords.\n' + '\n' + 'See also:\n' + '\n' + ' * **PEP 634** – Structural Pattern Matching: Specification\n' + '\n' + ' * **PEP 636** – Structural Pattern Matching: Tutorial\n' + '\n' + '\n' + 'Overview\n' + '--------\n' + '\n' + 'Here’s an overview of the logical flow of a match statement:\n' + '\n' + '1. The subject expression "subject_expr" is evaluated and a ' + 'resulting\n' + ' subject value obtained. If the subject expression contains a ' + 'comma,\n' + ' a tuple is constructed using the standard rules.\n' + '\n' + '2. Each pattern in a "case_block" is attempted to match with ' + 'the\n' + ' subject value. The specific rules for success or failure are\n' + ' described below. The match attempt can also bind some or all ' + 'of the\n' + ' standalone names within the pattern. The precise pattern ' + 'binding\n' + ' rules vary per pattern type and are specified below. **Name\n' + ' bindings made during a successful pattern match outlive the\n' + ' executed block and can be used after the match statement**.\n' + '\n' + ' Note:\n' + '\n' + ' During failed pattern matches, some subpatterns may ' + 'succeed. Do\n' + ' not rely on bindings being made for a failed match. ' + 'Conversely,\n' + ' do not rely on variables remaining unchanged after a ' + 'failed\n' + ' match. The exact behavior is dependent on implementation ' + 'and may\n' + ' vary. This is an intentional decision made to allow ' + 'different\n' + ' implementations to add optimizations.\n' + '\n' + '3. If the pattern succeeds, the corresponding guard (if present) ' + 'is\n' + ' evaluated. In this case all name bindings are guaranteed to ' + 'have\n' + ' happened.\n' + '\n' + ' * If the guard evaluates as true or is missing, the "block" ' + 'inside\n' + ' "case_block" is executed.\n' + '\n' + ' * Otherwise, the next "case_block" is attempted as described ' + 'above.\n' + '\n' + ' * If there are no further case blocks, the match statement ' + 'is\n' + ' completed.\n' + '\n' + 'Note:\n' + '\n' + ' Users should generally never rely on a pattern being ' + 'evaluated.\n' + ' Depending on implementation, the interpreter may cache values ' + 'or use\n' + ' other optimizations which skip repeated evaluations.\n' + '\n' + 'A sample match statement:\n' + '\n' + ' >>> flag = False\n' + ' >>> match (100, 200):\n' + ' ... case (100, 300): # Mismatch: 200 != 300\n' + " ... print('Case 1')\n" + ' ... case (100, 200) if flag: # Successful match, but ' + 'guard fails\n' + " ... print('Case 2')\n" + ' ... case (100, y): # Matches and binds y to 200\n' + " ... print(f'Case 3, y: {y}')\n" + ' ... case _: # Pattern not attempted\n' + " ... print('Case 4, I match anything!')\n" + ' ...\n' + ' Case 3, y: 200\n' + '\n' + 'In this case, "if flag" is a guard. Read more about that in the ' + 'next\n' + 'section.\n' + '\n' + '\n' + 'Guards\n' + '------\n' + '\n' + ' guard ::= "if" named_expression\n' + '\n' + 'A "guard" (which is part of the "case") must succeed for code ' + 'inside\n' + 'the "case" block to execute. It takes the form: "if" followed ' + 'by an\n' + 'expression.\n' + '\n' + 'The logical flow of a "case" block with a "guard" follows:\n' + '\n' + '1. Check that the pattern in the "case" block succeeded. If ' + 'the\n' + ' pattern failed, the "guard" is not evaluated and the next ' + '"case"\n' + ' block is checked.\n' + '\n' + '2. If the pattern succeeded, evaluate the "guard".\n' + '\n' + ' * If the "guard" condition evaluates as true, the case block ' + 'is\n' + ' selected.\n' + '\n' + ' * If the "guard" condition evaluates as false, the case block ' + 'is\n' + ' not selected.\n' + '\n' + ' * If the "guard" raises an exception during evaluation, the\n' + ' exception bubbles up.\n' + '\n' + 'Guards are allowed to have side effects as they are ' + 'expressions.\n' + 'Guard evaluation must proceed from the first to the last case ' + 'block,\n' + 'one at a time, skipping case blocks whose pattern(s) don’t all\n' + 'succeed. (I.e., guard evaluation must happen in order.) Guard\n' + 'evaluation must stop once a case block is selected.\n' + '\n' + '\n' + 'Irrefutable Case Blocks\n' + '-----------------------\n' + '\n' + 'An irrefutable case block is a match-all case block. A match\n' + 'statement may have at most one irrefutable case block, and it ' + 'must be\n' + 'last.\n' + '\n' + 'A case block is considered irrefutable if it has no guard and ' + 'its\n' + 'pattern is irrefutable. A pattern is considered irrefutable if ' + 'we can\n' + 'prove from its syntax alone that it will always succeed. Only ' + 'the\n' + 'following patterns are irrefutable:\n' + '\n' + '* AS Patterns whose left-hand side is irrefutable\n' + '\n' + '* OR Patterns containing at least one irrefutable pattern\n' + '\n' + '* Capture Patterns\n' + '\n' + '* Wildcard Patterns\n' + '\n' + '* parenthesized irrefutable patterns\n' + '\n' + '\n' + 'Patterns\n' + '--------\n' + '\n' + 'Note:\n' + '\n' + ' This section uses grammar notations beyond standard EBNF:\n' + '\n' + ' * the notation "SEP.RULE+" is shorthand for "RULE (SEP ' + 'RULE)*"\n' + '\n' + ' * the notation "!RULE" is shorthand for a negative lookahead\n' + ' assertion\n' + '\n' + 'The top-level syntax for "patterns" is:\n' + '\n' + ' patterns ::= open_sequence_pattern | pattern\n' + ' pattern ::= as_pattern | or_pattern\n' + ' closed_pattern ::= | literal_pattern\n' + ' | capture_pattern\n' + ' | wildcard_pattern\n' + ' | value_pattern\n' + ' | group_pattern\n' + ' | sequence_pattern\n' + ' | mapping_pattern\n' + ' | class_pattern\n' + '\n' + 'The descriptions below will include a description “in simple ' + 'terms” of\n' + 'what a pattern does for illustration purposes (credits to ' + 'Raymond\n' + 'Hettinger for a document that inspired most of the ' + 'descriptions). Note\n' + 'that these descriptions are purely for illustration purposes and ' + '**may\n' + 'not** reflect the underlying implementation. Furthermore, they ' + 'do not\n' + 'cover all valid forms.\n' + '\n' + '\n' + 'OR Patterns\n' + '~~~~~~~~~~~\n' + '\n' + 'An OR pattern is two or more patterns separated by vertical bars ' + '"|".\n' + 'Syntax:\n' + '\n' + ' or_pattern ::= "|".closed_pattern+\n' + '\n' + 'Only the final subpattern may be irrefutable, and each ' + 'subpattern must\n' + 'bind the same set of names to avoid ambiguity.\n' + '\n' + 'An OR pattern matches each of its subpatterns in turn to the ' + 'subject\n' + 'value, until one succeeds. The OR pattern is then considered\n' + 'successful. Otherwise, if none of the subpatterns succeed, the ' + 'OR\n' + 'pattern fails.\n' + '\n' + 'In simple terms, "P1 | P2 | ..." will try to match "P1", if it ' + 'fails\n' + 'it will try to match "P2", succeeding immediately if any ' + 'succeeds,\n' + 'failing otherwise.\n' + '\n' + '\n' + 'AS Patterns\n' + '~~~~~~~~~~~\n' + '\n' + 'An AS pattern matches an OR pattern on the left of the "as" ' + 'keyword\n' + 'against a subject. Syntax:\n' + '\n' + ' as_pattern ::= or_pattern "as" capture_pattern\n' + '\n' + 'If the OR pattern fails, the AS pattern fails. Otherwise, the ' + 'AS\n' + 'pattern binds the subject to the name on the right of the as ' + 'keyword\n' + 'and succeeds. "capture_pattern" cannot be a "_".\n' + '\n' + 'In simple terms "P as NAME" will match with "P", and on success ' + 'it\n' + 'will set "NAME = ".\n' + '\n' + '\n' + 'Literal Patterns\n' + '~~~~~~~~~~~~~~~~\n' + '\n' + 'A literal pattern corresponds to most literals in Python. ' + 'Syntax:\n' + '\n' + ' literal_pattern ::= signed_number\n' + ' | signed_number "+" NUMBER\n' + ' | signed_number "-" NUMBER\n' + ' | strings\n' + ' | "None"\n' + ' | "True"\n' + ' | "False"\n' + ' signed_number ::= ["-"] NUMBER\n' + '\n' + 'The rule "strings" and the token "NUMBER" are defined in the ' + 'standard\n' + 'Python grammar. Triple-quoted strings are supported. Raw ' + 'strings and\n' + 'byte strings are supported. f-strings are not supported.\n' + '\n' + 'The forms "signed_number \'+\' NUMBER" and "signed_number \'-\' ' + 'NUMBER"\n' + 'are for expressing complex numbers; they require a real number ' + 'on the\n' + 'left and an imaginary number on the right. E.g. "3 + 4j".\n' + '\n' + 'In simple terms, "LITERAL" will succeed only if " ==\n' + 'LITERAL". For the singletons "None", "True" and "False", the ' + '"is"\n' + 'operator is used.\n' + '\n' + '\n' + 'Capture Patterns\n' + '~~~~~~~~~~~~~~~~\n' + '\n' + 'A capture pattern binds the subject value to a name. Syntax:\n' + '\n' + " capture_pattern ::= !'_' NAME\n" + '\n' + 'A single underscore "_" is not a capture pattern (this is what ' + '"!\'_\'"\n' + 'expresses). It is instead treated as a "wildcard_pattern".\n' + '\n' + 'In a given pattern, a given name can only be bound once. E.g. ' + '"case\n' + 'x, x: ..." is invalid while "case [x] | x: ..." is allowed.\n' + '\n' + 'Capture patterns always succeed. The binding follows scoping ' + 'rules\n' + 'established by the assignment expression operator in **PEP ' + '572**; the\n' + 'name becomes a local variable in the closest containing function ' + 'scope\n' + 'unless there’s an applicable "global" or "nonlocal" statement.\n' + '\n' + 'In simple terms "NAME" will always succeed and it will set "NAME ' + '=\n' + '".\n' + '\n' + '\n' + 'Wildcard Patterns\n' + '~~~~~~~~~~~~~~~~~\n' + '\n' + 'A wildcard pattern always succeeds (matches anything) and binds ' + 'no\n' + 'name. Syntax:\n' + '\n' + " wildcard_pattern ::= '_'\n" + '\n' + '"_" is a soft keyword within any pattern, but only within ' + 'patterns.\n' + 'It is an identifier, as usual, even within "match" subject\n' + 'expressions, "guard"s, and "case" blocks.\n' + '\n' + 'In simple terms, "_" will always succeed.\n' + '\n' + '\n' + 'Value Patterns\n' + '~~~~~~~~~~~~~~\n' + '\n' + 'A value pattern represents a named value in Python. Syntax:\n' + '\n' + ' value_pattern ::= attr\n' + ' attr ::= name_or_attr "." NAME\n' + ' name_or_attr ::= attr | NAME\n' + '\n' + 'The dotted name in the pattern is looked up using standard ' + 'Python name\n' + 'resolution rules. The pattern succeeds if the value found ' + 'compares\n' + 'equal to the subject value (using the "==" equality operator).\n' + '\n' + 'In simple terms "NAME1.NAME2" will succeed only if " ' + '==\n' + 'NAME1.NAME2"\n' + '\n' + 'Note:\n' + '\n' + ' If the same value occurs multiple times in the same match ' + 'statement,\n' + ' the interpreter may cache the first value found and reuse it ' + 'rather\n' + ' than repeat the same lookup. This cache is strictly tied to a ' + 'given\n' + ' execution of a given match statement.\n' + '\n' + '\n' + 'Group Patterns\n' + '~~~~~~~~~~~~~~\n' + '\n' + 'A group pattern allows users to add parentheses around patterns ' + 'to\n' + 'emphasize the intended grouping. Otherwise, it has no ' + 'additional\n' + 'syntax. Syntax:\n' + '\n' + ' group_pattern ::= "(" pattern ")"\n' + '\n' + 'In simple terms "(P)" has the same effect as "P".\n' + '\n' + '\n' + 'Sequence Patterns\n' + '~~~~~~~~~~~~~~~~~\n' + '\n' + 'A sequence pattern contains several subpatterns to be matched ' + 'against\n' + 'sequence elements. The syntax is similar to the unpacking of a ' + 'list or\n' + 'tuple.\n' + '\n' + ' sequence_pattern ::= "[" [maybe_sequence_pattern] "]"\n' + ' | "(" [open_sequence_pattern] ")"\n' + ' open_sequence_pattern ::= maybe_star_pattern "," ' + '[maybe_sequence_pattern]\n' + ' maybe_sequence_pattern ::= ",".maybe_star_pattern+ ","?\n' + ' maybe_star_pattern ::= star_pattern | pattern\n' + ' star_pattern ::= "*" (capture_pattern | ' + 'wildcard_pattern)\n' + '\n' + 'There is no difference if parentheses or square brackets are ' + 'used for\n' + 'sequence patterns (i.e. "(...)" vs "[...]" ).\n' + '\n' + 'Note:\n' + '\n' + ' A single pattern enclosed in parentheses without a trailing ' + 'comma\n' + ' (e.g. "(3 | 4)") is a group pattern. While a single pattern ' + 'enclosed\n' + ' in square brackets (e.g. "[3 | 4]") is still a sequence ' + 'pattern.\n' + '\n' + 'At most one star subpattern may be in a sequence pattern. The ' + 'star\n' + 'subpattern may occur in any position. If no star subpattern is\n' + 'present, the sequence pattern is a fixed-length sequence ' + 'pattern;\n' + 'otherwise it is a variable-length sequence pattern.\n' + '\n' + 'The following is the logical flow for matching a sequence ' + 'pattern\n' + 'against a subject value:\n' + '\n' + '1. If the subject value is not a sequence [2], the sequence ' + 'pattern\n' + ' fails.\n' + '\n' + '2. If the subject value is an instance of "str", "bytes" or\n' + ' "bytearray" the sequence pattern fails.\n' + '\n' + '3. The subsequent steps depend on whether the sequence pattern ' + 'is\n' + ' fixed or variable-length.\n' + '\n' + ' If the sequence pattern is fixed-length:\n' + '\n' + ' 1. If the length of the subject sequence is not equal to the ' + 'number\n' + ' of subpatterns, the sequence pattern fails\n' + '\n' + ' 2. Subpatterns in the sequence pattern are matched to their\n' + ' corresponding items in the subject sequence from left to ' + 'right.\n' + ' Matching stops as soon as a subpattern fails. If all\n' + ' subpatterns succeed in matching their corresponding item, ' + 'the\n' + ' sequence pattern succeeds.\n' + '\n' + ' Otherwise, if the sequence pattern is variable-length:\n' + '\n' + ' 1. If the length of the subject sequence is less than the ' + 'number of\n' + ' non-star subpatterns, the sequence pattern fails.\n' + '\n' + ' 2. The leading non-star subpatterns are matched to their\n' + ' corresponding items as for fixed-length sequences.\n' + '\n' + ' 3. If the previous step succeeds, the star subpattern matches ' + 'a\n' + ' list formed of the remaining subject items, excluding the\n' + ' remaining items corresponding to non-star subpatterns ' + 'following\n' + ' the star subpattern.\n' + '\n' + ' 4. Remaining non-star subpatterns are matched to their\n' + ' corresponding subject items, as for a fixed-length ' + 'sequence.\n' + '\n' + ' Note:\n' + '\n' + ' The length of the subject sequence is obtained via "len()" ' + '(i.e.\n' + ' via the "__len__()" protocol). This length may be cached ' + 'by the\n' + ' interpreter in a similar manner as value patterns.\n' + '\n' + 'In simple terms "[P1, P2, P3," … ", P]" matches only if all ' + 'the\n' + 'following happens:\n' + '\n' + '* check "" is a sequence\n' + '\n' + '* "len(subject) == "\n' + '\n' + '* "P1" matches "[0]" (note that this match can also ' + 'bind\n' + ' names)\n' + '\n' + '* "P2" matches "[1]" (note that this match can also ' + 'bind\n' + ' names)\n' + '\n' + '* … and so on for the corresponding pattern/element.\n' + '\n' + '\n' + 'Mapping Patterns\n' + '~~~~~~~~~~~~~~~~\n' + '\n' + 'A mapping pattern contains one or more key-value patterns. The ' + 'syntax\n' + 'is similar to the construction of a dictionary. Syntax:\n' + '\n' + ' mapping_pattern ::= "{" [items_pattern] "}"\n' + ' items_pattern ::= ",".key_value_pattern+ ","?\n' + ' key_value_pattern ::= (literal_pattern | value_pattern) ":" ' + 'pattern\n' + ' | double_star_pattern\n' + ' double_star_pattern ::= "**" capture_pattern\n' + '\n' + 'At most one double star pattern may be in a mapping pattern. ' + 'The\n' + 'double star pattern must be the last subpattern in the mapping\n' + 'pattern.\n' + '\n' + 'Duplicate keys in mapping patterns are disallowed. Duplicate ' + 'literal\n' + 'keys will raise a "SyntaxError". Two keys that otherwise have ' + 'the same\n' + 'value will raise a "ValueError" at runtime.\n' + '\n' + 'The following is the logical flow for matching a mapping ' + 'pattern\n' + 'against a subject value:\n' + '\n' + '1. If the subject value is not a mapping [3],the mapping ' + 'pattern\n' + ' fails.\n' + '\n' + '2. If every key given in the mapping pattern is present in the ' + 'subject\n' + ' mapping, and the pattern for each key matches the ' + 'corresponding\n' + ' item of the subject mapping, the mapping pattern succeeds.\n' + '\n' + '3. If duplicate keys are detected in the mapping pattern, the ' + 'pattern\n' + ' is considered invalid. A "SyntaxError" is raised for ' + 'duplicate\n' + ' literal values; or a "ValueError" for named keys of the same ' + 'value.\n' + '\n' + 'Note:\n' + '\n' + ' Key-value pairs are matched using the two-argument form of ' + 'the\n' + ' mapping subject’s "get()" method. Matched key-value pairs ' + 'must\n' + ' already be present in the mapping, and not created on-the-fly ' + 'via\n' + ' "__missing__()" or "__getitem__()".\n' + '\n' + 'In simple terms "{KEY1: P1, KEY2: P2, ... }" matches only if all ' + 'the\n' + 'following happens:\n' + '\n' + '* check "" is a mapping\n' + '\n' + '* "KEY1 in "\n' + '\n' + '* "P1" matches "[KEY1]"\n' + '\n' + '* … and so on for the corresponding KEY/pattern pair.\n' + '\n' + '\n' + 'Class Patterns\n' + '~~~~~~~~~~~~~~\n' + '\n' + 'A class pattern represents a class and its positional and ' + 'keyword\n' + 'arguments (if any). Syntax:\n' + '\n' + ' class_pattern ::= name_or_attr "(" [pattern_arguments ' + '","?] ")"\n' + ' pattern_arguments ::= positional_patterns ["," ' + 'keyword_patterns]\n' + ' | keyword_patterns\n' + ' positional_patterns ::= ",".pattern+\n' + ' keyword_patterns ::= ",".keyword_pattern+\n' + ' keyword_pattern ::= NAME "=" pattern\n' + '\n' + 'The same keyword should not be repeated in class patterns.\n' + '\n' + 'The following is the logical flow for matching a class pattern ' + 'against\n' + 'a subject value:\n' + '\n' + '1. If "name_or_attr" is not an instance of the builtin "type" , ' + 'raise\n' + ' "TypeError".\n' + '\n' + '2. If the subject value is not an instance of "name_or_attr" ' + '(tested\n' + ' via "isinstance()"), the class pattern fails.\n' + '\n' + '3. If no pattern arguments are present, the pattern succeeds.\n' + ' Otherwise, the subsequent steps depend on whether keyword or\n' + ' positional argument patterns are present.\n' + '\n' + ' For a number of built-in types (specified below), a single\n' + ' positional subpattern is accepted which will match the ' + 'entire\n' + ' subject; for these types keyword patterns also work as for ' + 'other\n' + ' types.\n' + '\n' + ' If only keyword patterns are present, they are processed as\n' + ' follows, one by one:\n' + '\n' + ' I. The keyword is looked up as an attribute on the subject.\n' + '\n' + ' * If this raises an exception other than "AttributeError", ' + 'the\n' + ' exception bubbles up.\n' + '\n' + ' * If this raises "AttributeError", the class pattern has ' + 'failed.\n' + '\n' + ' * Else, the subpattern associated with the keyword pattern ' + 'is\n' + ' matched against the subject’s attribute value. If this ' + 'fails,\n' + ' the class pattern fails; if this succeeds, the match ' + 'proceeds\n' + ' to the next keyword.\n' + '\n' + ' II. If all keyword patterns succeed, the class pattern ' + 'succeeds.\n' + '\n' + ' If any positional patterns are present, they are converted ' + 'to\n' + ' keyword patterns using the "__match_args__" attribute on the ' + 'class\n' + ' "name_or_attr" before matching:\n' + '\n' + ' I. The equivalent of "getattr(cls, "__match_args__", ())" is\n' + ' called.\n' + '\n' + ' * If this raises an exception, the exception bubbles up.\n' + '\n' + ' * If the returned value is not a tuple, the conversion ' + 'fails and\n' + ' "TypeError" is raised.\n' + '\n' + ' * If there are more positional patterns than\n' + ' "len(cls.__match_args__)", "TypeError" is raised.\n' + '\n' + ' * Otherwise, positional pattern "i" is converted to a ' + 'keyword\n' + ' pattern using "__match_args__[i]" as the keyword.\n' + ' "__match_args__[i]" must be a string; if not "TypeError" ' + 'is\n' + ' raised.\n' + '\n' + ' * If there are duplicate keywords, "TypeError" is raised.\n' + '\n' + ' See also:\n' + '\n' + ' Customizing positional arguments in class pattern ' + 'matching\n' + '\n' + ' II. Once all positional patterns have been converted to ' + 'keyword\n' + ' patterns,\n' + ' the match proceeds as if there were only keyword ' + 'patterns.\n' + '\n' + ' For the following built-in types the handling of positional\n' + ' subpatterns is different:\n' + '\n' + ' * "bool"\n' + '\n' + ' * "bytearray"\n' + '\n' + ' * "bytes"\n' + '\n' + ' * "dict"\n' + '\n' + ' * "float"\n' + '\n' + ' * "frozenset"\n' + '\n' + ' * "int"\n' + '\n' + ' * "list"\n' + '\n' + ' * "set"\n' + '\n' + ' * "str"\n' + '\n' + ' * "tuple"\n' + '\n' + ' These classes accept a single positional argument, and the ' + 'pattern\n' + ' there is matched against the whole object rather than an ' + 'attribute.\n' + ' For example "int(0|1)" matches the value "0", but not the ' + 'value\n' + ' "0.0".\n' + '\n' + 'In simple terms "CLS(P1, attr=P2)" matches only if the ' + 'following\n' + 'happens:\n' + '\n' + '* "isinstance(, CLS)"\n' + '\n' + '* convert "P1" to a keyword pattern using "CLS.__match_args__"\n' + '\n' + '* For each keyword argument "attr=P2":\n' + '\n' + ' * "hasattr(, "attr")"\n' + '\n' + ' * "P2" matches ".attr"\n' + '\n' + '* … and so on for the corresponding keyword argument/pattern ' + 'pair.\n' + '\n' + 'See also:\n' + '\n' + ' * **PEP 634** – Structural Pattern Matching: Specification\n' + '\n' + ' * **PEP 636** – Structural Pattern Matching: Tutorial\n' + '\n' + '\n' + 'Function definitions\n' + '====================\n' + '\n' + 'A function definition defines a user-defined function object ' + '(see\n' + 'section The standard type hierarchy):\n' + '\n' + ' funcdef ::= [decorators] "def" funcname ' + '[type_params] "(" [parameter_list] ")"\n' + ' ["->" expression] ":" suite\n' + ' decorators ::= decorator+\n' + ' decorator ::= "@" assignment_expression ' + 'NEWLINE\n' + ' parameter_list ::= defparameter ("," ' + 'defparameter)* "," "/" ["," [parameter_list_no_posonly]]\n' + ' | parameter_list_no_posonly\n' + ' parameter_list_no_posonly ::= defparameter ("," ' + 'defparameter)* ["," [parameter_list_starargs]]\n' + ' | parameter_list_starargs\n' + ' parameter_list_starargs ::= "*" [star_parameter] ("," ' + 'defparameter)* ["," ["**" parameter [","]]]\n' + ' | "**" parameter [","]\n' + ' parameter ::= identifier [":" expression]\n' + ' star_parameter ::= identifier [":" ["*"] ' + 'expression]\n' + ' defparameter ::= parameter ["=" expression]\n' + ' funcname ::= identifier\n' + '\n' + 'A function definition is an executable statement. Its execution ' + 'binds\n' + 'the function name in the current local namespace to a function ' + 'object\n' + '(a wrapper around the executable code for the function). This\n' + 'function object contains a reference to the current global ' + 'namespace\n' + 'as the global namespace to be used when the function is called.\n' + '\n' + 'The function definition does not execute the function body; this ' + 'gets\n' + 'executed only when the function is called. [4]\n' + '\n' + 'A function definition may be wrapped by one or more *decorator*\n' + 'expressions. Decorator expressions are evaluated when the ' + 'function is\n' + 'defined, in the scope that contains the function definition. ' + 'The\n' + 'result must be a callable, which is invoked with the function ' + 'object\n' + 'as the only argument. The returned value is bound to the ' + 'function name\n' + 'instead of the function object. Multiple decorators are applied ' + 'in\n' + 'nested fashion. For example, the following code\n' + '\n' + ' @f1(arg)\n' + ' @f2\n' + ' def func(): pass\n' + '\n' + 'is roughly equivalent to\n' + '\n' + ' def func(): pass\n' + ' func = f1(arg)(f2(func))\n' + '\n' + 'except that the original function is not temporarily bound to ' + 'the name\n' + '"func".\n' + '\n' + 'Changed in version 3.9: Functions may be decorated with any ' + 'valid\n' + '"assignment_expression". Previously, the grammar was much more\n' + 'restrictive; see **PEP 614** for details.\n' + '\n' + 'A list of type parameters may be given in square brackets ' + 'between the\n' + 'function’s name and the opening parenthesis for its parameter ' + 'list.\n' + 'This indicates to static type checkers that the function is ' + 'generic.\n' + 'At runtime, the type parameters can be retrieved from the ' + 'function’s\n' + '"__type_params__" attribute. See Generic functions for more.\n' + '\n' + 'Changed in version 3.12: Type parameter lists are new in Python ' + '3.12.\n' + '\n' + 'When one or more *parameters* have the form *parameter* "="\n' + '*expression*, the function is said to have “default parameter ' + 'values.”\n' + 'For a parameter with a default value, the corresponding ' + '*argument* may\n' + 'be omitted from a call, in which case the parameter’s default ' + 'value is\n' + 'substituted. If a parameter has a default value, all following\n' + 'parameters up until the “"*"” must also have a default value — ' + 'this is\n' + 'a syntactic restriction that is not expressed by the grammar.\n' + '\n' + '**Default parameter values are evaluated from left to right when ' + 'the\n' + 'function definition is executed.** This means that the ' + 'expression is\n' + 'evaluated once, when the function is defined, and that the same ' + '“pre-\n' + 'computed” value is used for each call. This is especially ' + 'important\n' + 'to understand when a default parameter value is a mutable ' + 'object, such\n' + 'as a list or a dictionary: if the function modifies the object ' + '(e.g.\n' + 'by appending an item to a list), the default parameter value is ' + 'in\n' + 'effect modified. This is generally not what was intended. A ' + 'way\n' + 'around this is to use "None" as the default, and explicitly test ' + 'for\n' + 'it in the body of the function, e.g.:\n' + '\n' + ' def whats_on_the_telly(penguin=None):\n' + ' if penguin is None:\n' + ' penguin = []\n' + ' penguin.append("property of the zoo")\n' + ' return penguin\n' + '\n' + 'Function call semantics are described in more detail in section ' + 'Calls.\n' + 'A function call always assigns values to all parameters ' + 'mentioned in\n' + 'the parameter list, either from positional arguments, from ' + 'keyword\n' + 'arguments, or from default values. If the form “"*identifier"” ' + 'is\n' + 'present, it is initialized to a tuple receiving any excess ' + 'positional\n' + 'parameters, defaulting to the empty tuple. If the form\n' + '“"**identifier"” is present, it is initialized to a new ordered\n' + 'mapping receiving any excess keyword arguments, defaulting to a ' + 'new\n' + 'empty mapping of the same type. Parameters after “"*"” or\n' + '“"*identifier"” are keyword-only parameters and may only be ' + 'passed by\n' + 'keyword arguments. Parameters before “"/"” are positional-only\n' + 'parameters and may only be passed by positional arguments.\n' + '\n' + 'Changed in version 3.8: The "/" function parameter syntax may be ' + 'used\n' + 'to indicate positional-only parameters. See **PEP 570** for ' + 'details.\n' + '\n' + 'Parameters may have an *annotation* of the form “": ' + 'expression"”\n' + 'following the parameter name. Any parameter may have an ' + 'annotation,\n' + 'even those of the form "*identifier" or "**identifier". (As a ' + 'special\n' + 'case, parameters of the form "*identifier" may have an ' + 'annotation “":\n' + '*expression"”.) Functions may have “return” annotation of the ' + 'form\n' + '“"-> expression"” after the parameter list. These annotations ' + 'can be\n' + 'any valid Python expression. The presence of annotations does ' + 'not\n' + 'change the semantics of a function. The annotation values are\n' + 'available as values of a dictionary keyed by the parameters’ ' + 'names in\n' + 'the "__annotations__" attribute of the function object. If the\n' + '"annotations" import from "__future__" is used, annotations are\n' + 'preserved as strings at runtime which enables postponed ' + 'evaluation.\n' + 'Otherwise, they are evaluated when the function definition is\n' + 'executed. In this case annotations may be evaluated in a ' + 'different\n' + 'order than they appear in the source code.\n' + '\n' + 'Changed in version 3.11: Parameters of the form “"*identifier"” ' + 'may\n' + 'have an annotation “": *expression"”. See **PEP 646**.\n' + '\n' + 'It is also possible to create anonymous functions (functions not ' + 'bound\n' + 'to a name), for immediate use in expressions. This uses lambda\n' + 'expressions, described in section Lambdas. Note that the ' + 'lambda\n' + 'expression is merely a shorthand for a simplified function ' + 'definition;\n' + 'a function defined in a “"def"” statement can be passed around ' + 'or\n' + 'assigned to another name just like a function defined by a ' + 'lambda\n' + 'expression. The “"def"” form is actually more powerful since ' + 'it\n' + 'allows the execution of multiple statements and annotations.\n' + '\n' + '**Programmer’s note:** Functions are first-class objects. A ' + '“"def"”\n' + 'statement executed inside a function definition defines a local\n' + 'function that can be returned or passed around. Free variables ' + 'used\n' + 'in the nested function can access the local variables of the ' + 'function\n' + 'containing the def. See section Naming and binding for ' + 'details.\n' + '\n' + 'See also:\n' + '\n' + ' **PEP 3107** - Function Annotations\n' + ' The original specification for function annotations.\n' + '\n' + ' **PEP 484** - Type Hints\n' + ' Definition of a standard meaning for annotations: type ' + 'hints.\n' + '\n' + ' **PEP 526** - Syntax for Variable Annotations\n' + ' Ability to type hint variable declarations, including ' + 'class\n' + ' variables and instance variables.\n' + '\n' + ' **PEP 563** - Postponed Evaluation of Annotations\n' + ' Support for forward references within annotations by ' + 'preserving\n' + ' annotations in a string form at runtime instead of eager\n' + ' evaluation.\n' + '\n' + ' **PEP 318** - Decorators for Functions and Methods\n' + ' Function and method decorators were introduced. Class ' + 'decorators\n' + ' were introduced in **PEP 3129**.\n' + '\n' + '\n' + 'Class definitions\n' + '=================\n' + '\n' + 'A class definition defines a class object (see section The ' + 'standard\n' + 'type hierarchy):\n' + '\n' + ' classdef ::= [decorators] "class" classname [type_params] ' + '[inheritance] ":" suite\n' + ' inheritance ::= "(" [argument_list] ")"\n' + ' classname ::= identifier\n' + '\n' + 'A class definition is an executable statement. The inheritance ' + 'list\n' + 'usually gives a list of base classes (see Metaclasses for more\n' + 'advanced uses), so each item in the list should evaluate to a ' + 'class\n' + 'object which allows subclassing. Classes without an inheritance ' + 'list\n' + 'inherit, by default, from the base class "object"; hence,\n' + '\n' + ' class Foo:\n' + ' pass\n' + '\n' + 'is equivalent to\n' + '\n' + ' class Foo(object):\n' + ' pass\n' + '\n' + 'The class’s suite is then executed in a new execution frame ' + '(see\n' + 'Naming and binding), using a newly created local namespace and ' + 'the\n' + 'original global namespace. (Usually, the suite contains mostly\n' + 'function definitions.) When the class’s suite finishes ' + 'execution, its\n' + 'execution frame is discarded but its local namespace is saved. ' + '[5] A\n' + 'class object is then created using the inheritance list for the ' + 'base\n' + 'classes and the saved local namespace for the attribute ' + 'dictionary.\n' + 'The class name is bound to this class object in the original ' + 'local\n' + 'namespace.\n' + '\n' + 'The order in which attributes are defined in the class body is\n' + 'preserved in the new class’s "__dict__". Note that this is ' + 'reliable\n' + 'only right after the class is created and only for classes that ' + 'were\n' + 'defined using the definition syntax.\n' + '\n' + 'Class creation can be customized heavily using metaclasses.\n' + '\n' + 'Classes can also be decorated: just like when decorating ' + 'functions,\n' + '\n' + ' @f1(arg)\n' + ' @f2\n' + ' class Foo: pass\n' + '\n' + 'is roughly equivalent to\n' + '\n' + ' class Foo: pass\n' + ' Foo = f1(arg)(f2(Foo))\n' + '\n' + 'The evaluation rules for the decorator expressions are the same ' + 'as for\n' + 'function decorators. The result is then bound to the class ' + 'name.\n' + '\n' + 'Changed in version 3.9: Classes may be decorated with any valid\n' + '"assignment_expression". Previously, the grammar was much more\n' + 'restrictive; see **PEP 614** for details.\n' + '\n' + 'A list of type parameters may be given in square brackets ' + 'immediately\n' + 'after the class’s name. This indicates to static type checkers ' + 'that\n' + 'the class is generic. At runtime, the type parameters can be ' + 'retrieved\n' + 'from the class’s "__type_params__" attribute. See Generic ' + 'classes for\n' + 'more.\n' + '\n' + 'Changed in version 3.12: Type parameter lists are new in Python ' + '3.12.\n' + '\n' + '**Programmer’s note:** Variables defined in the class definition ' + 'are\n' + 'class attributes; they are shared by instances. Instance ' + 'attributes\n' + 'can be set in a method with "self.name = value". Both class ' + 'and\n' + 'instance attributes are accessible through the notation ' + '“"self.name"”,\n' + 'and an instance attribute hides a class attribute with the same ' + 'name\n' + 'when accessed in this way. Class attributes can be used as ' + 'defaults\n' + 'for instance attributes, but using mutable values there can lead ' + 'to\n' + 'unexpected results. Descriptors can be used to create instance\n' + 'variables with different implementation details.\n' + '\n' + 'See also:\n' + '\n' + ' **PEP 3115** - Metaclasses in Python 3000\n' + ' The proposal that changed the declaration of metaclasses to ' + 'the\n' + ' current syntax, and the semantics for how classes with\n' + ' metaclasses are constructed.\n' + '\n' + ' **PEP 3129** - Class Decorators\n' + ' The proposal that added class decorators. Function and ' + 'method\n' + ' decorators were introduced in **PEP 318**.\n' + '\n' + '\n' + 'Coroutines\n' + '==========\n' + '\n' + 'Added in version 3.5.\n' + '\n' + '\n' + 'Coroutine function definition\n' + '-----------------------------\n' + '\n' + ' async_funcdef ::= [decorators] "async" "def" funcname "(" ' + '[parameter_list] ")"\n' + ' ["->" expression] ":" suite\n' + '\n' + 'Execution of Python coroutines can be suspended and resumed at ' + 'many\n' + 'points (see *coroutine*). "await" expressions, "async for" and ' + '"async\n' + 'with" can only be used in the body of a coroutine function.\n' + '\n' + 'Functions defined with "async def" syntax are always coroutine\n' + 'functions, even if they do not contain "await" or "async" ' + 'keywords.\n' + '\n' + 'It is a "SyntaxError" to use a "yield from" expression inside ' + 'the body\n' + 'of a coroutine function.\n' + '\n' + 'An example of a coroutine function:\n' + '\n' + ' async def func(param1, param2):\n' + ' do_stuff()\n' + ' await some_coroutine()\n' + '\n' + 'Changed in version 3.7: "await" and "async" are now keywords;\n' + 'previously they were only treated as such inside the body of a\n' + 'coroutine function.\n' + '\n' + '\n' + 'The "async for" statement\n' + '-------------------------\n' + '\n' + ' async_for_stmt ::= "async" for_stmt\n' + '\n' + 'An *asynchronous iterable* provides an "__aiter__" method that\n' + 'directly returns an *asynchronous iterator*, which can call\n' + 'asynchronous code in its "__anext__" method.\n' + '\n' + 'The "async for" statement allows convenient iteration over\n' + 'asynchronous iterables.\n' + '\n' + 'The following code:\n' + '\n' + ' async for TARGET in ITER:\n' + ' SUITE\n' + ' else:\n' + ' SUITE2\n' + '\n' + 'Is semantically equivalent to:\n' + '\n' + ' iter = (ITER)\n' + ' iter = type(iter).__aiter__(iter)\n' + ' running = True\n' + '\n' + ' while running:\n' + ' try:\n' + ' TARGET = await type(iter).__anext__(iter)\n' + ' except StopAsyncIteration:\n' + ' running = False\n' + ' else:\n' + ' SUITE\n' + ' else:\n' + ' SUITE2\n' + '\n' + 'See also "__aiter__()" and "__anext__()" for details.\n' + '\n' + 'It is a "SyntaxError" to use an "async for" statement outside ' + 'the body\n' + 'of a coroutine function.\n' + '\n' + '\n' + 'The "async with" statement\n' + '--------------------------\n' + '\n' + ' async_with_stmt ::= "async" with_stmt\n' + '\n' + 'An *asynchronous context manager* is a *context manager* that is ' + 'able\n' + 'to suspend execution in its *enter* and *exit* methods.\n' + '\n' + 'The following code:\n' + '\n' + ' async with EXPRESSION as TARGET:\n' + ' SUITE\n' + '\n' + 'is semantically equivalent to:\n' + '\n' + ' manager = (EXPRESSION)\n' + ' aenter = type(manager).__aenter__\n' + ' aexit = type(manager).__aexit__\n' + ' value = await aenter(manager)\n' + ' hit_except = False\n' + '\n' + ' try:\n' + ' TARGET = value\n' + ' SUITE\n' + ' except:\n' + ' hit_except = True\n' + ' if not await aexit(manager, *sys.exc_info()):\n' + ' raise\n' + ' finally:\n' + ' if not hit_except:\n' + ' await aexit(manager, None, None, None)\n' + '\n' + 'See also "__aenter__()" and "__aexit__()" for details.\n' + '\n' + 'It is a "SyntaxError" to use an "async with" statement outside ' + 'the\n' + 'body of a coroutine function.\n' + '\n' + 'See also:\n' + '\n' + ' **PEP 492** - Coroutines with async and await syntax\n' + ' The proposal that made coroutines a proper standalone ' + 'concept in\n' + ' Python, and added supporting syntax.\n' + '\n' + '\n' + 'Type parameter lists\n' + '====================\n' + '\n' + 'Added in version 3.12.\n' + '\n' + ' type_params ::= "[" type_param ("," type_param)* "]"\n' + ' type_param ::= typevar | typevartuple | paramspec\n' + ' typevar ::= identifier (":" expression)?\n' + ' typevartuple ::= "*" identifier\n' + ' paramspec ::= "**" identifier\n' + '\n' + 'Functions (including coroutines), classes and type aliases may ' + 'contain\n' + 'a type parameter list:\n' + '\n' + ' def max[T](args: list[T]) -> T:\n' + ' ...\n' + '\n' + ' async def amax[T](args: list[T]) -> T:\n' + ' ...\n' + '\n' + ' class Bag[T]:\n' + ' def __iter__(self) -> Iterator[T]:\n' + ' ...\n' + '\n' + ' def add(self, arg: T) -> None:\n' + ' ...\n' + '\n' + ' type ListOrSet[T] = list[T] | set[T]\n' + '\n' + 'Semantically, this indicates that the function, class, or type ' + 'alias\n' + 'is generic over a type variable. This information is primarily ' + 'used by\n' + 'static type checkers, and at runtime, generic objects behave ' + 'much like\n' + 'their non-generic counterparts.\n' + '\n' + 'Type parameters are declared in square brackets ("[]") ' + 'immediately\n' + 'after the name of the function, class, or type alias. The type\n' + 'parameters are accessible within the scope of the generic ' + 'object, but\n' + 'not elsewhere. Thus, after a declaration "def func[T](): pass", ' + 'the\n' + 'name "T" is not available in the module scope. Below, the ' + 'semantics of\n' + 'generic objects are described with more precision. The scope of ' + 'type\n' + 'parameters is modeled with a special function (technically, an\n' + 'annotation scope) that wraps the creation of the generic ' + 'object.\n' + '\n' + 'Generic functions, classes, and type aliases have a ' + '"__type_params__"\n' + 'attribute listing their type parameters.\n' + '\n' + 'Type parameters come in three kinds:\n' + '\n' + '* "typing.TypeVar", introduced by a plain name (e.g., "T").\n' + ' Semantically, this represents a single type to a type ' + 'checker.\n' + '\n' + '* "typing.TypeVarTuple", introduced by a name prefixed with a ' + 'single\n' + ' asterisk (e.g., "*Ts"). Semantically, this stands for a tuple ' + 'of any\n' + ' number of types.\n' + '\n' + '* "typing.ParamSpec", introduced by a name prefixed with two ' + 'asterisks\n' + ' (e.g., "**P"). Semantically, this stands for the parameters of ' + 'a\n' + ' callable.\n' + '\n' + '"typing.TypeVar" declarations can define *bounds* and ' + '*constraints*\n' + 'with a colon (":") followed by an expression. A single ' + 'expression\n' + 'after the colon indicates a bound (e.g. "T: int"). Semantically, ' + 'this\n' + 'means that the "typing.TypeVar" can only represent types that ' + 'are a\n' + 'subtype of this bound. A parenthesized tuple of expressions ' + 'after the\n' + 'colon indicates a set of constraints (e.g. "T: (str, bytes)"). ' + 'Each\n' + 'member of the tuple should be a type (again, this is not ' + 'enforced at\n' + 'runtime). Constrained type variables can only take on one of the ' + 'types\n' + 'in the list of constraints.\n' + '\n' + 'For "typing.TypeVar"s declared using the type parameter list ' + 'syntax,\n' + 'the bound and constraints are not evaluated when the generic ' + 'object is\n' + 'created, but only when the value is explicitly accessed through ' + 'the\n' + 'attributes "__bound__" and "__constraints__". To accomplish ' + 'this, the\n' + 'bounds or constraints are evaluated in a separate annotation ' + 'scope.\n' + '\n' + '"typing.TypeVarTuple"s and "typing.ParamSpec"s cannot have ' + 'bounds or\n' + 'constraints.\n' + '\n' + 'The following example indicates the full set of allowed type ' + 'parameter\n' + 'declarations:\n' + '\n' + ' def overly_generic[\n' + ' SimpleTypeVar,\n' + ' TypeVarWithBound: int,\n' + ' TypeVarWithConstraints: (str, bytes),\n' + ' *SimpleTypeVarTuple,\n' + ' **SimpleParamSpec,\n' + ' ](\n' + ' a: SimpleTypeVar,\n' + ' b: TypeVarWithBound,\n' + ' c: Callable[SimpleParamSpec, TypeVarWithConstraints],\n' + ' *d: SimpleTypeVarTuple,\n' + ' ): ...\n' + '\n' + '\n' + 'Generic functions\n' + '-----------------\n' + '\n' + 'Generic functions are declared as follows:\n' + '\n' + ' def func[T](arg: T): ...\n' + '\n' + 'This syntax is equivalent to:\n' + '\n' + ' annotation-def TYPE_PARAMS_OF_func():\n' + ' T = typing.TypeVar("T")\n' + ' def func(arg: T): ...\n' + ' func.__type_params__ = (T,)\n' + ' return func\n' + ' func = TYPE_PARAMS_OF_func()\n' + '\n' + 'Here "annotation-def" indicates an annotation scope, which is ' + 'not\n' + 'actually bound to any name at runtime. (One other liberty is ' + 'taken in\n' + 'the translation: the syntax does not go through attribute access ' + 'on\n' + 'the "typing" module, but creates an instance of ' + '"typing.TypeVar"\n' + 'directly.)\n' + '\n' + 'The annotations of generic functions are evaluated within the\n' + 'annotation scope used for declaring the type parameters, but ' + 'the\n' + 'function’s defaults and decorators are not.\n' + '\n' + 'The following example illustrates the scoping rules for these ' + 'cases,\n' + 'as well as for additional flavors of type parameters:\n' + '\n' + ' @decorator\n' + ' def func[T: int, *Ts, **P](*args: *Ts, arg: Callable[P, T] = ' + 'some_default):\n' + ' ...\n' + '\n' + 'Except for the lazy evaluation of the "TypeVar" bound, this is\n' + 'equivalent to:\n' + '\n' + ' DEFAULT_OF_arg = some_default\n' + '\n' + ' annotation-def TYPE_PARAMS_OF_func():\n' + '\n' + ' annotation-def BOUND_OF_T():\n' + ' return int\n' + ' # In reality, BOUND_OF_T() is evaluated only on demand.\n' + ' T = typing.TypeVar("T", bound=BOUND_OF_T())\n' + '\n' + ' Ts = typing.TypeVarTuple("Ts")\n' + ' P = typing.ParamSpec("P")\n' + '\n' + ' def func(*args: *Ts, arg: Callable[P, T] = ' + 'DEFAULT_OF_arg):\n' + ' ...\n' + '\n' + ' func.__type_params__ = (T, Ts, P)\n' + ' return func\n' + ' func = decorator(TYPE_PARAMS_OF_func())\n' + '\n' + 'The capitalized names like "DEFAULT_OF_arg" are not actually ' + 'bound at\n' + 'runtime.\n' + '\n' + '\n' + 'Generic classes\n' + '---------------\n' + '\n' + 'Generic classes are declared as follows:\n' + '\n' + ' class Bag[T]: ...\n' + '\n' + 'This syntax is equivalent to:\n' + '\n' + ' annotation-def TYPE_PARAMS_OF_Bag():\n' + ' T = typing.TypeVar("T")\n' + ' class Bag(typing.Generic[T]):\n' + ' __type_params__ = (T,)\n' + ' ...\n' + ' return Bag\n' + ' Bag = TYPE_PARAMS_OF_Bag()\n' + '\n' + 'Here again "annotation-def" (not a real keyword) indicates an\n' + 'annotation scope, and the name "TYPE_PARAMS_OF_Bag" is not ' + 'actually\n' + 'bound at runtime.\n' + '\n' + 'Generic classes implicitly inherit from "typing.Generic". The ' + 'base\n' + 'classes and keyword arguments of generic classes are evaluated ' + 'within\n' + 'the type scope for the type parameters, and decorators are ' + 'evaluated\n' + 'outside that scope. This is illustrated by this example:\n' + '\n' + ' @decorator\n' + ' class Bag(Base[T], arg=T): ...\n' + '\n' + 'This is equivalent to:\n' + '\n' + ' annotation-def TYPE_PARAMS_OF_Bag():\n' + ' T = typing.TypeVar("T")\n' + ' class Bag(Base[T], typing.Generic[T], arg=T):\n' + ' __type_params__ = (T,)\n' + ' ...\n' + ' return Bag\n' + ' Bag = decorator(TYPE_PARAMS_OF_Bag())\n' + '\n' + '\n' + 'Generic type aliases\n' + '--------------------\n' + '\n' + 'The "type" statement can also be used to create a generic type ' + 'alias:\n' + '\n' + ' type ListOrSet[T] = list[T] | set[T]\n' + '\n' + 'Except for the lazy evaluation of the value, this is equivalent ' + 'to:\n' + '\n' + ' annotation-def TYPE_PARAMS_OF_ListOrSet():\n' + ' T = typing.TypeVar("T")\n' + '\n' + ' annotation-def VALUE_OF_ListOrSet():\n' + ' return list[T] | set[T]\n' + ' # In reality, the value is lazily evaluated\n' + ' return typing.TypeAliasType("ListOrSet", ' + 'VALUE_OF_ListOrSet(), type_params=(T,))\n' + ' ListOrSet = TYPE_PARAMS_OF_ListOrSet()\n' + '\n' + 'Here, "annotation-def" (not a real keyword) indicates an ' + 'annotation\n' + 'scope. The capitalized names like "TYPE_PARAMS_OF_ListOrSet" are ' + 'not\n' + 'actually bound at runtime.\n' + '\n' + '-[ Footnotes ]-\n' + '\n' + '[1] The exception is propagated to the invocation stack unless ' + 'there\n' + ' is a "finally" clause which happens to raise another ' + 'exception.\n' + ' That new exception causes the old one to be lost.\n' + '\n' + '[2] In pattern matching, a sequence is defined as one of the\n' + ' following:\n' + '\n' + ' * a class that inherits from "collections.abc.Sequence"\n' + '\n' + ' * a Python class that has been registered as\n' + ' "collections.abc.Sequence"\n' + '\n' + ' * a builtin class that has its (CPython) ' + '"Py_TPFLAGS_SEQUENCE" bit\n' + ' set\n' + '\n' + ' * a class that inherits from any of the above\n' + '\n' + ' The following standard library classes are sequences:\n' + '\n' + ' * "array.array"\n' + '\n' + ' * "collections.deque"\n' + '\n' + ' * "list"\n' + '\n' + ' * "memoryview"\n' + '\n' + ' * "range"\n' + '\n' + ' * "tuple"\n' + '\n' + ' Note:\n' + '\n' + ' Subject values of type "str", "bytes", and "bytearray" do ' + 'not\n' + ' match sequence patterns.\n' + '\n' + '[3] In pattern matching, a mapping is defined as one of the ' + 'following:\n' + '\n' + ' * a class that inherits from "collections.abc.Mapping"\n' + '\n' + ' * a Python class that has been registered as\n' + ' "collections.abc.Mapping"\n' + '\n' + ' * a builtin class that has its (CPython) ' + '"Py_TPFLAGS_MAPPING" bit\n' + ' set\n' + '\n' + ' * a class that inherits from any of the above\n' + '\n' + ' The standard library classes "dict" and ' + '"types.MappingProxyType"\n' + ' are mappings.\n' + '\n' + '[4] A string literal appearing as the first statement in the ' + 'function\n' + ' body is transformed into the function’s "__doc__" attribute ' + 'and\n' + ' therefore the function’s *docstring*.\n' + '\n' + '[5] A string literal appearing as the first statement in the ' + 'class\n' + ' body is transformed into the namespace’s "__doc__" item and\n' + ' therefore the class’s *docstring*.\n', + 'context-managers': 'With Statement Context Managers\n' + '*******************************\n' + '\n' + 'A *context manager* is an object that defines the ' + 'runtime context to\n' + 'be established when executing a "with" statement. The ' + 'context manager\n' + 'handles the entry into, and the exit from, the desired ' + 'runtime context\n' + 'for the execution of the block of code. Context ' + 'managers are normally\n' + 'invoked using the "with" statement (described in section ' + 'The with\n' + 'statement), but can also be used by directly invoking ' + 'their methods.\n' + '\n' + 'Typical uses of context managers include saving and ' + 'restoring various\n' + 'kinds of global state, locking and unlocking resources, ' + 'closing opened\n' + 'files, etc.\n' + '\n' + 'For more information on context managers, see Context ' + 'Manager Types.\n' + 'The "object" class itself does not provide the context ' + 'manager\n' + 'methods.\n' + '\n' + 'object.__enter__(self)\n' + '\n' + ' Enter the runtime context related to this object. The ' + '"with"\n' + ' statement will bind this method’s return value to the ' + 'target(s)\n' + ' specified in the "as" clause of the statement, if ' + 'any.\n' + '\n' + 'object.__exit__(self, exc_type, exc_value, traceback)\n' + '\n' + ' Exit the runtime context related to this object. The ' + 'parameters\n' + ' describe the exception that caused the context to be ' + 'exited. If the\n' + ' context was exited without an exception, all three ' + 'arguments will\n' + ' be "None".\n' + '\n' + ' If an exception is supplied, and the method wishes to ' + 'suppress the\n' + ' exception (i.e., prevent it from being propagated), ' + 'it should\n' + ' return a true value. Otherwise, the exception will be ' + 'processed\n' + ' normally upon exit from this method.\n' + '\n' + ' Note that "__exit__()" methods should not reraise the ' + 'passed-in\n' + ' exception; this is the caller’s responsibility.\n' + '\n' + 'See also:\n' + '\n' + ' **PEP 343** - The “with” statement\n' + ' The specification, background, and examples for the ' + 'Python "with"\n' + ' statement.\n', + 'continue': 'The "continue" statement\n' + '************************\n' + '\n' + ' continue_stmt ::= "continue"\n' + '\n' + '"continue" may only occur syntactically nested in a "for" or ' + '"while"\n' + 'loop, but not nested in a function or class definition within ' + 'that\n' + 'loop. It continues with the next cycle of the nearest enclosing ' + 'loop.\n' + '\n' + 'When "continue" passes control out of a "try" statement with a\n' + '"finally" clause, that "finally" clause is executed before ' + 'really\n' + 'starting the next loop cycle.\n', + 'conversions': 'Arithmetic conversions\n' + '**********************\n' + '\n' + 'When a description of an arithmetic operator below uses the ' + 'phrase\n' + '“the numeric arguments are converted to a common type”, this ' + 'means\n' + 'that the operator implementation for built-in types works as ' + 'follows:\n' + '\n' + '* If either argument is a complex number, the other is ' + 'converted to\n' + ' complex;\n' + '\n' + '* otherwise, if either argument is a floating-point number, ' + 'the other\n' + ' is converted to floating point;\n' + '\n' + '* otherwise, both must be integers and no conversion is ' + 'necessary.\n' + '\n' + 'Some additional rules apply for certain operators (e.g., a ' + 'string as a\n' + 'left argument to the ‘%’ operator). Extensions must define ' + 'their own\n' + 'conversion behavior.\n', + 'customization': 'Basic customization\n' + '*******************\n' + '\n' + 'object.__new__(cls[, ...])\n' + '\n' + ' Called to create a new instance of class *cls*. ' + '"__new__()" is a\n' + ' static method (special-cased so you need not declare it ' + 'as such)\n' + ' that takes the class of which an instance was requested ' + 'as its\n' + ' first argument. The remaining arguments are those ' + 'passed to the\n' + ' object constructor expression (the call to the class). ' + 'The return\n' + ' value of "__new__()" should be the new object instance ' + '(usually an\n' + ' instance of *cls*).\n' + '\n' + ' Typical implementations create a new instance of the ' + 'class by\n' + ' invoking the superclass’s "__new__()" method using\n' + ' "super().__new__(cls[, ...])" with appropriate arguments ' + 'and then\n' + ' modifying the newly created instance as necessary before ' + 'returning\n' + ' it.\n' + '\n' + ' If "__new__()" is invoked during object construction and ' + 'it returns\n' + ' an instance of *cls*, then the new instance’s ' + '"__init__()" method\n' + ' will be invoked like "__init__(self[, ...])", where ' + '*self* is the\n' + ' new instance and the remaining arguments are the same as ' + 'were\n' + ' passed to the object constructor.\n' + '\n' + ' If "__new__()" does not return an instance of *cls*, ' + 'then the new\n' + ' instance’s "__init__()" method will not be invoked.\n' + '\n' + ' "__new__()" is intended mainly to allow subclasses of ' + 'immutable\n' + ' types (like int, str, or tuple) to customize instance ' + 'creation. It\n' + ' is also commonly overridden in custom metaclasses in ' + 'order to\n' + ' customize class creation.\n' + '\n' + 'object.__init__(self[, ...])\n' + '\n' + ' Called after the instance has been created (by ' + '"__new__()"), but\n' + ' before it is returned to the caller. The arguments are ' + 'those\n' + ' passed to the class constructor expression. If a base ' + 'class has an\n' + ' "__init__()" method, the derived class’s "__init__()" ' + 'method, if\n' + ' any, must explicitly call it to ensure proper ' + 'initialization of the\n' + ' base class part of the instance; for example:\n' + ' "super().__init__([args...])".\n' + '\n' + ' Because "__new__()" and "__init__()" work together in ' + 'constructing\n' + ' objects ("__new__()" to create it, and "__init__()" to ' + 'customize\n' + ' it), no non-"None" value may be returned by ' + '"__init__()"; doing so\n' + ' will cause a "TypeError" to be raised at runtime.\n' + '\n' + 'object.__del__(self)\n' + '\n' + ' Called when the instance is about to be destroyed. This ' + 'is also\n' + ' called a finalizer or (improperly) a destructor. If a ' + 'base class\n' + ' has a "__del__()" method, the derived class’s ' + '"__del__()" method,\n' + ' if any, must explicitly call it to ensure proper ' + 'deletion of the\n' + ' base class part of the instance.\n' + '\n' + ' It is possible (though not recommended!) for the ' + '"__del__()" method\n' + ' to postpone destruction of the instance by creating a ' + 'new reference\n' + ' to it. This is called object *resurrection*. It is\n' + ' implementation-dependent whether "__del__()" is called a ' + 'second\n' + ' time when a resurrected object is about to be destroyed; ' + 'the\n' + ' current *CPython* implementation only calls it once.\n' + '\n' + ' It is not guaranteed that "__del__()" methods are called ' + 'for\n' + ' objects that still exist when the interpreter exits.\n' + ' "weakref.finalize" provides a straightforward way to ' + 'register a\n' + ' cleanup function to be called when an object is garbage ' + 'collected.\n' + '\n' + ' Note:\n' + '\n' + ' "del x" doesn’t directly call "x.__del__()" — the ' + 'former\n' + ' decrements the reference count for "x" by one, and the ' + 'latter is\n' + ' only called when "x"’s reference count reaches zero.\n' + '\n' + ' **CPython implementation detail:** It is possible for a ' + 'reference\n' + ' cycle to prevent the reference count of an object from ' + 'going to\n' + ' zero. In this case, the cycle will be later detected ' + 'and deleted\n' + ' by the *cyclic garbage collector*. A common cause of ' + 'reference\n' + ' cycles is when an exception has been caught in a local ' + 'variable.\n' + ' The frame’s locals then reference the exception, which ' + 'references\n' + ' its own traceback, which references the locals of all ' + 'frames caught\n' + ' in the traceback.\n' + '\n' + ' See also: Documentation for the "gc" module.\n' + '\n' + ' Warning:\n' + '\n' + ' Due to the precarious circumstances under which ' + '"__del__()"\n' + ' methods are invoked, exceptions that occur during ' + 'their execution\n' + ' are ignored, and a warning is printed to "sys.stderr" ' + 'instead.\n' + ' In particular:\n' + '\n' + ' * "__del__()" can be invoked when arbitrary code is ' + 'being\n' + ' executed, including from any arbitrary thread. If ' + '"__del__()"\n' + ' needs to take a lock or invoke any other blocking ' + 'resource, it\n' + ' may deadlock as the resource may already be taken by ' + 'the code\n' + ' that gets interrupted to execute "__del__()".\n' + '\n' + ' * "__del__()" can be executed during interpreter ' + 'shutdown. As a\n' + ' consequence, the global variables it needs to access ' + '(including\n' + ' other modules) may already have been deleted or set ' + 'to "None".\n' + ' Python guarantees that globals whose name begins ' + 'with a single\n' + ' underscore are deleted from their module before ' + 'other globals\n' + ' are deleted; if no other references to such globals ' + 'exist, this\n' + ' may help in assuring that imported modules are still ' + 'available\n' + ' at the time when the "__del__()" method is called.\n' + '\n' + 'object.__repr__(self)\n' + '\n' + ' Called by the "repr()" built-in function to compute the ' + '“official”\n' + ' string representation of an object. If at all possible, ' + 'this\n' + ' should look like a valid Python expression that could be ' + 'used to\n' + ' recreate an object with the same value (given an ' + 'appropriate\n' + ' environment). If this is not possible, a string of the ' + 'form\n' + ' "<...some useful description...>" should be returned. ' + 'The return\n' + ' value must be a string object. If a class defines ' + '"__repr__()" but\n' + ' not "__str__()", then "__repr__()" is also used when an ' + '“informal”\n' + ' string representation of instances of that class is ' + 'required.\n' + '\n' + ' This is typically used for debugging, so it is important ' + 'that the\n' + ' representation is information-rich and unambiguous. A ' + 'default\n' + ' implementation is provided by the "object" class ' + 'itself.\n' + '\n' + 'object.__str__(self)\n' + '\n' + ' Called by "str(object)", the default "__format__()" ' + 'implementation,\n' + ' and the built-in function "print()", to compute the ' + '“informal” or\n' + ' nicely printable string representation of an object. ' + 'The return\n' + ' value must be a str object.\n' + '\n' + ' This method differs from "object.__repr__()" in that ' + 'there is no\n' + ' expectation that "__str__()" return a valid Python ' + 'expression: a\n' + ' more convenient or concise representation can be used.\n' + '\n' + ' The default implementation defined by the built-in type ' + '"object"\n' + ' calls "object.__repr__()".\n' + '\n' + 'object.__bytes__(self)\n' + '\n' + ' Called by bytes to compute a byte-string representation ' + 'of an\n' + ' object. This should return a "bytes" object. The ' + '"object" class\n' + ' itself does not provide this method.\n' + '\n' + 'object.__format__(self, format_spec)\n' + '\n' + ' Called by the "format()" built-in function, and by ' + 'extension,\n' + ' evaluation of formatted string literals and the ' + '"str.format()"\n' + ' method, to produce a “formatted” string representation ' + 'of an\n' + ' object. The *format_spec* argument is a string that ' + 'contains a\n' + ' description of the formatting options desired. The ' + 'interpretation\n' + ' of the *format_spec* argument is up to the type ' + 'implementing\n' + ' "__format__()", however most classes will either ' + 'delegate\n' + ' formatting to one of the built-in types, or use a ' + 'similar\n' + ' formatting option syntax.\n' + '\n' + ' See Format Specification Mini-Language for a description ' + 'of the\n' + ' standard formatting syntax.\n' + '\n' + ' The return value must be a string object.\n' + '\n' + ' The default implementation by the "object" class should ' + 'be given an\n' + ' empty *format_spec* string. It delegates to ' + '"__str__()".\n' + '\n' + ' Changed in version 3.4: The __format__ method of ' + '"object" itself\n' + ' raises a "TypeError" if passed any non-empty string.\n' + '\n' + ' Changed in version 3.7: "object.__format__(x, \'\')" is ' + 'now\n' + ' equivalent to "str(x)" rather than "format(str(x), ' + '\'\')".\n' + '\n' + 'object.__lt__(self, other)\n' + 'object.__le__(self, other)\n' + 'object.__eq__(self, other)\n' + 'object.__ne__(self, other)\n' + 'object.__gt__(self, other)\n' + 'object.__ge__(self, other)\n' + '\n' + ' These are the so-called “rich comparison” methods. The\n' + ' correspondence between operator symbols and method names ' + 'is as\n' + ' follows: "xy" calls\n' + ' "x.__gt__(y)", and "x>=y" calls "x.__ge__(y)".\n' + '\n' + ' A rich comparison method may return the singleton ' + '"NotImplemented"\n' + ' if it does not implement the operation for a given pair ' + 'of\n' + ' arguments. By convention, "False" and "True" are ' + 'returned for a\n' + ' successful comparison. However, these methods can return ' + 'any value,\n' + ' so if the comparison operator is used in a Boolean ' + 'context (e.g.,\n' + ' in the condition of an "if" statement), Python will call ' + '"bool()"\n' + ' on the value to determine if the result is true or ' + 'false.\n' + '\n' + ' By default, "object" implements "__eq__()" by using ' + '"is", returning\n' + ' "NotImplemented" in the case of a false comparison: ' + '"True if x is y\n' + ' else NotImplemented". For "__ne__()", by default it ' + 'delegates to\n' + ' "__eq__()" and inverts the result unless it is ' + '"NotImplemented".\n' + ' There are no other implied relationships among the ' + 'comparison\n' + ' operators or default implementations; for example, the ' + 'truth of\n' + ' "(x.__hash__".\n' + '\n' + ' If a class that does not override "__eq__()" wishes to ' + 'suppress\n' + ' hash support, it should include "__hash__ = None" in the ' + 'class\n' + ' definition. A class which defines its own "__hash__()" ' + 'that\n' + ' explicitly raises a "TypeError" would be incorrectly ' + 'identified as\n' + ' hashable by an "isinstance(obj, ' + 'collections.abc.Hashable)" call.\n' + '\n' + ' Note:\n' + '\n' + ' By default, the "__hash__()" values of str and bytes ' + 'objects are\n' + ' “salted” with an unpredictable random value. Although ' + 'they\n' + ' remain constant within an individual Python process, ' + 'they are not\n' + ' predictable between repeated invocations of ' + 'Python.This is\n' + ' intended to provide protection against a ' + 'denial-of-service caused\n' + ' by carefully chosen inputs that exploit the worst ' + 'case\n' + ' performance of a dict insertion, *O*(*n*^2) ' + 'complexity. See\n' + ' http://ocert.org/advisories/ocert-2011-003.html for\n' + ' details.Changing hash values affects the iteration ' + 'order of sets.\n' + ' Python has never made guarantees about this ordering ' + '(and it\n' + ' typically varies between 32-bit and 64-bit builds).See ' + 'also\n' + ' "PYTHONHASHSEED".\n' + '\n' + ' Changed in version 3.3: Hash randomization is enabled by ' + 'default.\n' + '\n' + 'object.__bool__(self)\n' + '\n' + ' Called to implement truth value testing and the built-in ' + 'operation\n' + ' "bool()"; should return "False" or "True". When this ' + 'method is not\n' + ' defined, "__len__()" is called, if it is defined, and ' + 'the object is\n' + ' considered true if its result is nonzero. If a class ' + 'defines\n' + ' neither "__len__()" nor "__bool__()" (which is true of ' + 'the "object"\n' + ' class itself), all its instances are considered true.\n', + 'debugger': '"pdb" — The Python Debugger\n' + '***************************\n' + '\n' + '**Source code:** Lib/pdb.py\n' + '\n' + '======================================================================\n' + '\n' + 'The module "pdb" defines an interactive source code debugger ' + 'for\n' + 'Python programs. It supports setting (conditional) breakpoints ' + 'and\n' + 'single stepping at the source line level, inspection of stack ' + 'frames,\n' + 'source code listing, and evaluation of arbitrary Python code in ' + 'the\n' + 'context of any stack frame. It also supports post-mortem ' + 'debugging\n' + 'and can be called under program control.\n' + '\n' + 'The debugger is extensible – it is actually defined as the ' + 'class\n' + '"Pdb". This is currently undocumented but easily understood by ' + 'reading\n' + 'the source. The extension interface uses the modules "bdb" and ' + '"cmd".\n' + '\n' + 'See also:\n' + '\n' + ' Module "faulthandler"\n' + ' Used to dump Python tracebacks explicitly, on a fault, ' + 'after a\n' + ' timeout, or on a user signal.\n' + '\n' + ' Module "traceback"\n' + ' Standard interface to extract, format and print stack ' + 'traces of\n' + ' Python programs.\n' + '\n' + 'The typical usage to break into the debugger is to insert:\n' + '\n' + ' import pdb; pdb.set_trace()\n' + '\n' + 'Or:\n' + '\n' + ' breakpoint()\n' + '\n' + 'at the location you want to break into the debugger, and then ' + 'run the\n' + 'program. You can then step through the code following this ' + 'statement,\n' + 'and continue running without the debugger using the "continue"\n' + 'command.\n' + '\n' + 'Changed in version 3.7: The built-in "breakpoint()", when called ' + 'with\n' + 'defaults, can be used instead of "import pdb; pdb.set_trace()".\n' + '\n' + ' def double(x):\n' + ' breakpoint()\n' + ' return x * 2\n' + ' val = 3\n' + ' print(f"{val} * 2 is {double(val)}")\n' + '\n' + 'The debugger’s prompt is "(Pdb)", which is the indicator that ' + 'you are\n' + 'in debug mode:\n' + '\n' + ' > ...(3)double()\n' + ' -> return x * 2\n' + ' (Pdb) p x\n' + ' 3\n' + ' (Pdb) continue\n' + ' 3 * 2 is 6\n' + '\n' + 'Changed in version 3.3: Tab-completion via the "readline" module ' + 'is\n' + 'available for commands and command arguments, e.g. the current ' + 'global\n' + 'and local names are offered as arguments of the "p" command.\n' + '\n' + 'You can also invoke "pdb" from the command line to debug other\n' + 'scripts. For example:\n' + '\n' + ' python -m pdb myscript.py\n' + '\n' + 'When invoked as a module, pdb will automatically enter ' + 'post-mortem\n' + 'debugging if the program being debugged exits abnormally. After ' + 'post-\n' + 'mortem debugging (or after normal exit of the program), pdb ' + 'will\n' + 'restart the program. Automatic restarting preserves pdb’s state ' + '(such\n' + 'as breakpoints) and in most cases is more useful than quitting ' + 'the\n' + 'debugger upon program’s exit.\n' + '\n' + 'Changed in version 3.2: Added the "-c" option to execute ' + 'commands as\n' + 'if given in a ".pdbrc" file; see Debugger Commands.\n' + '\n' + 'Changed in version 3.7: Added the "-m" option to execute ' + 'modules\n' + 'similar to the way "python -m" does. As with a script, the ' + 'debugger\n' + 'will pause execution just before the first line of the module.\n' + '\n' + 'Typical usage to execute a statement under control of the ' + 'debugger is:\n' + '\n' + ' >>> import pdb\n' + ' >>> def f(x):\n' + ' ... print(1 / x)\n' + ' >>> pdb.run("f(2)")\n' + ' > (1)()\n' + ' (Pdb) continue\n' + ' 0.5\n' + ' >>>\n' + '\n' + 'The typical usage to inspect a crashed program is:\n' + '\n' + ' >>> import pdb\n' + ' >>> def f(x):\n' + ' ... print(1 / x)\n' + ' ...\n' + ' >>> f(0)\n' + ' Traceback (most recent call last):\n' + ' File "", line 1, in \n' + ' File "", line 2, in f\n' + ' ZeroDivisionError: division by zero\n' + ' >>> pdb.pm()\n' + ' > (2)f()\n' + ' (Pdb) p x\n' + ' 0\n' + ' (Pdb)\n' + '\n' + 'The module defines the following functions; each enters the ' + 'debugger\n' + 'in a slightly different way:\n' + '\n' + 'pdb.run(statement, globals=None, locals=None)\n' + '\n' + ' Execute the *statement* (given as a string or a code object) ' + 'under\n' + ' debugger control. The debugger prompt appears before any ' + 'code is\n' + ' executed; you can set breakpoints and type "continue", or you ' + 'can\n' + ' step through the statement using "step" or "next" (all these\n' + ' commands are explained below). The optional *globals* and ' + '*locals*\n' + ' arguments specify the environment in which the code is ' + 'executed; by\n' + ' default the dictionary of the module "__main__" is used. ' + '(See the\n' + ' explanation of the built-in "exec()" or "eval()" functions.)\n' + '\n' + 'pdb.runeval(expression, globals=None, locals=None)\n' + '\n' + ' Evaluate the *expression* (given as a string or a code ' + 'object)\n' + ' under debugger control. When "runeval()" returns, it returns ' + 'the\n' + ' value of the *expression*. Otherwise this function is ' + 'similar to\n' + ' "run()".\n' + '\n' + 'pdb.runcall(function, *args, **kwds)\n' + '\n' + ' Call the *function* (a function or method object, not a ' + 'string)\n' + ' with the given arguments. When "runcall()" returns, it ' + 'returns\n' + ' whatever the function call returned. The debugger prompt ' + 'appears\n' + ' as soon as the function is entered.\n' + '\n' + 'pdb.set_trace(*, header=None)\n' + '\n' + ' Enter the debugger at the calling stack frame. This is ' + 'useful to\n' + ' hard-code a breakpoint at a given point in a program, even if ' + 'the\n' + ' code is not otherwise being debugged (e.g. when an assertion\n' + ' fails). If given, *header* is printed to the console just ' + 'before\n' + ' debugging begins.\n' + '\n' + ' Changed in version 3.7: The keyword-only argument *header*.\n' + '\n' + 'pdb.post_mortem(traceback=None)\n' + '\n' + ' Enter post-mortem debugging of the given *traceback* object. ' + 'If no\n' + ' *traceback* is given, it uses the one of the exception that ' + 'is\n' + ' currently being handled (an exception must be being handled ' + 'if the\n' + ' default is to be used).\n' + '\n' + 'pdb.pm()\n' + '\n' + ' Enter post-mortem debugging of the traceback found in\n' + ' "sys.last_traceback".\n' + '\n' + 'The "run*" functions and "set_trace()" are aliases for ' + 'instantiating\n' + 'the "Pdb" class and calling the method of the same name. If you ' + 'want\n' + 'to access further features, you have to do this yourself:\n' + '\n' + "class pdb.Pdb(completekey='tab', stdin=None, stdout=None, " + 'skip=None, nosigint=False, readrc=True)\n' + '\n' + ' "Pdb" is the debugger class.\n' + '\n' + ' The *completekey*, *stdin* and *stdout* arguments are passed ' + 'to the\n' + ' underlying "cmd.Cmd" class; see the description there.\n' + '\n' + ' The *skip* argument, if given, must be an iterable of ' + 'glob-style\n' + ' module name patterns. The debugger will not step into frames ' + 'that\n' + ' originate in a module that matches one of these patterns. ' + '[1]\n' + '\n' + ' By default, Pdb sets a handler for the SIGINT signal (which ' + 'is sent\n' + ' when the user presses "Ctrl-C" on the console) when you give ' + 'a\n' + ' "continue" command. This allows you to break into the ' + 'debugger\n' + ' again by pressing "Ctrl-C". If you want Pdb not to touch ' + 'the\n' + ' SIGINT handler, set *nosigint* to true.\n' + '\n' + ' The *readrc* argument defaults to true and controls whether ' + 'Pdb\n' + ' will load .pdbrc files from the filesystem.\n' + '\n' + ' Example call to enable tracing with *skip*:\n' + '\n' + " import pdb; pdb.Pdb(skip=['django.*']).set_trace()\n" + '\n' + ' Raises an auditing event "pdb.Pdb" with no arguments.\n' + '\n' + ' Changed in version 3.1: Added the *skip* parameter.\n' + '\n' + ' Changed in version 3.2: Added the *nosigint* parameter. ' + 'Previously,\n' + ' a SIGINT handler was never set by Pdb.\n' + '\n' + ' Changed in version 3.6: The *readrc* argument.\n' + '\n' + ' run(statement, globals=None, locals=None)\n' + ' runeval(expression, globals=None, locals=None)\n' + ' runcall(function, *args, **kwds)\n' + ' set_trace()\n' + '\n' + ' See the documentation for the functions explained above.\n' + '\n' + '\n' + 'Debugger Commands\n' + '=================\n' + '\n' + 'The commands recognized by the debugger are listed below. Most\n' + 'commands can be abbreviated to one or two letters as indicated; ' + 'e.g.\n' + '"h(elp)" means that either "h" or "help" can be used to enter ' + 'the help\n' + 'command (but not "he" or "hel", nor "H" or "Help" or "HELP").\n' + 'Arguments to commands must be separated by whitespace (spaces ' + 'or\n' + 'tabs). Optional arguments are enclosed in square brackets ' + '("[]") in\n' + 'the command syntax; the square brackets must not be typed.\n' + 'Alternatives in the command syntax are separated by a vertical ' + 'bar\n' + '("|").\n' + '\n' + 'Entering a blank line repeats the last command entered. ' + 'Exception: if\n' + 'the last command was a "list" command, the next 11 lines are ' + 'listed.\n' + '\n' + 'Commands that the debugger doesn’t recognize are assumed to be ' + 'Python\n' + 'statements and are executed in the context of the program being\n' + 'debugged. Python statements can also be prefixed with an ' + 'exclamation\n' + 'point ("!"). This is a powerful way to inspect the program ' + 'being\n' + 'debugged; it is even possible to change a variable or call a ' + 'function.\n' + 'When an exception occurs in such a statement, the exception name ' + 'is\n' + 'printed but the debugger’s state is not changed.\n' + '\n' + 'The debugger supports aliases. Aliases can have parameters ' + 'which\n' + 'allows one a certain level of adaptability to the context under\n' + 'examination.\n' + '\n' + 'Multiple commands may be entered on a single line, separated by ' + '";;".\n' + '(A single ";" is not used as it is the separator for multiple ' + 'commands\n' + 'in a line that is passed to the Python parser.) No intelligence ' + 'is\n' + 'applied to separating the commands; the input is split at the ' + 'first\n' + '";;" pair, even if it is in the middle of a quoted string. A\n' + 'workaround for strings with double semicolons is to use ' + 'implicit\n' + 'string concatenation "\';\'\';\'" or "";"";"".\n' + '\n' + 'To set a temporary global variable, use a *convenience ' + 'variable*. A\n' + '*convenience variable* is a variable whose name starts with ' + '"$". For\n' + 'example, "$foo = 1" sets a global variable "$foo" which you can ' + 'use in\n' + 'the debugger session. The *convenience variables* are cleared ' + 'when\n' + 'the program resumes execution so it’s less likely to interfere ' + 'with\n' + 'your program compared to using normal variables like "foo = 1".\n' + '\n' + 'There are three preset *convenience variables*:\n' + '\n' + '* "$_frame": the current frame you are debugging\n' + '\n' + '* "$_retval": the return value if the frame is returning\n' + '\n' + '* "$_exception": the exception if the frame is raising an ' + 'exception\n' + '\n' + 'Added in version 3.12: Added the *convenience variable* ' + 'feature.\n' + '\n' + 'If a file ".pdbrc" exists in the user’s home directory or in ' + 'the\n' + 'current directory, it is read with "\'utf-8\'" encoding and ' + 'executed as\n' + 'if it had been typed at the debugger prompt, with the exception ' + 'that\n' + 'empty lines and lines starting with "#" are ignored. This is\n' + 'particularly useful for aliases. If both files exist, the one ' + 'in the\n' + 'home directory is read first and aliases defined there can be\n' + 'overridden by the local file.\n' + '\n' + 'Changed in version 3.2: ".pdbrc" can now contain commands that\n' + 'continue debugging, such as "continue" or "next". Previously, ' + 'these\n' + 'commands had no effect.\n' + '\n' + 'Changed in version 3.11: ".pdbrc" is now read with "\'utf-8\'" ' + 'encoding.\n' + 'Previously, it was read with the system locale encoding.\n' + '\n' + 'h(elp) [command]\n' + '\n' + ' Without argument, print the list of available commands. With ' + 'a\n' + ' *command* as argument, print help about that command. "help ' + 'pdb"\n' + ' displays the full documentation (the docstring of the "pdb"\n' + ' module). Since the *command* argument must be an identifier, ' + '"help\n' + ' exec" must be entered to get help on the "!" command.\n' + '\n' + 'w(here)\n' + '\n' + ' Print a stack trace, with the most recent frame at the ' + 'bottom. An\n' + ' arrow (">") indicates the current frame, which determines ' + 'the\n' + ' context of most commands.\n' + '\n' + 'd(own) [count]\n' + '\n' + ' Move the current frame *count* (default one) levels down in ' + 'the\n' + ' stack trace (to a newer frame).\n' + '\n' + 'u(p) [count]\n' + '\n' + ' Move the current frame *count* (default one) levels up in the ' + 'stack\n' + ' trace (to an older frame).\n' + '\n' + 'b(reak) [([filename:]lineno | function) [, condition]]\n' + '\n' + ' With a *lineno* argument, set a break there in the current ' + 'file.\n' + ' With a *function* argument, set a break at the first ' + 'executable\n' + ' statement within that function. The line number may be ' + 'prefixed\n' + ' with a filename and a colon, to specify a breakpoint in ' + 'another\n' + ' file (probably one that hasn’t been loaded yet). The file ' + 'is\n' + ' searched on "sys.path". Note that each breakpoint is ' + 'assigned a\n' + ' number to which all the other breakpoint commands refer.\n' + '\n' + ' If a second argument is present, it is an expression which ' + 'must\n' + ' evaluate to true before the breakpoint is honored.\n' + '\n' + ' Without argument, list all breaks, including for each ' + 'breakpoint,\n' + ' the number of times that breakpoint has been hit, the ' + 'current\n' + ' ignore count, and the associated condition if any.\n' + '\n' + 'tbreak [([filename:]lineno | function) [, condition]]\n' + '\n' + ' Temporary breakpoint, which is removed automatically when it ' + 'is\n' + ' first hit. The arguments are the same as for "break".\n' + '\n' + 'cl(ear) [filename:lineno | bpnumber ...]\n' + '\n' + ' With a *filename:lineno* argument, clear all the breakpoints ' + 'at\n' + ' this line. With a space separated list of breakpoint numbers, ' + 'clear\n' + ' those breakpoints. Without argument, clear all breaks (but ' + 'first\n' + ' ask confirmation).\n' + '\n' + 'disable bpnumber [bpnumber ...]\n' + '\n' + ' Disable the breakpoints given as a space separated list of\n' + ' breakpoint numbers. Disabling a breakpoint means it cannot ' + 'cause\n' + ' the program to stop execution, but unlike clearing a ' + 'breakpoint, it\n' + ' remains in the list of breakpoints and can be (re-)enabled.\n' + '\n' + 'enable bpnumber [bpnumber ...]\n' + '\n' + ' Enable the breakpoints specified.\n' + '\n' + 'ignore bpnumber [count]\n' + '\n' + ' Set the ignore count for the given breakpoint number. If ' + '*count*\n' + ' is omitted, the ignore count is set to 0. A breakpoint ' + 'becomes\n' + ' active when the ignore count is zero. When non-zero, the ' + '*count*\n' + ' is decremented each time the breakpoint is reached and the\n' + ' breakpoint is not disabled and any associated condition ' + 'evaluates\n' + ' to true.\n' + '\n' + 'condition bpnumber [condition]\n' + '\n' + ' Set a new *condition* for the breakpoint, an expression which ' + 'must\n' + ' evaluate to true before the breakpoint is honored. If ' + '*condition*\n' + ' is absent, any existing condition is removed; i.e., the ' + 'breakpoint\n' + ' is made unconditional.\n' + '\n' + 'commands [bpnumber]\n' + '\n' + ' Specify a list of commands for breakpoint number *bpnumber*. ' + 'The\n' + ' commands themselves appear on the following lines. Type a ' + 'line\n' + ' containing just "end" to terminate the commands. An example:\n' + '\n' + ' (Pdb) commands 1\n' + ' (com) p some_variable\n' + ' (com) end\n' + ' (Pdb)\n' + '\n' + ' To remove all commands from a breakpoint, type "commands" ' + 'and\n' + ' follow it immediately with "end"; that is, give no commands.\n' + '\n' + ' With no *bpnumber* argument, "commands" refers to the last\n' + ' breakpoint set.\n' + '\n' + ' You can use breakpoint commands to start your program up ' + 'again.\n' + ' Simply use the "continue" command, or "step", or any other ' + 'command\n' + ' that resumes execution.\n' + '\n' + ' Specifying any command resuming execution (currently ' + '"continue",\n' + ' "step", "next", "return", "jump", "quit" and their ' + 'abbreviations)\n' + ' terminates the command list (as if that command was ' + 'immediately\n' + ' followed by end). This is because any time you resume ' + 'execution\n' + ' (even with a simple next or step), you may encounter another\n' + ' breakpoint—which could have its own command list, leading to\n' + ' ambiguities about which list to execute.\n' + '\n' + ' If you use the "silent" command in the command list, the ' + 'usual\n' + ' message about stopping at a breakpoint is not printed. This ' + 'may be\n' + ' desirable for breakpoints that are to print a specific ' + 'message and\n' + ' then continue. If none of the other commands print anything, ' + 'you\n' + ' see no sign that the breakpoint was reached.\n' + '\n' + 's(tep)\n' + '\n' + ' Execute the current line, stop at the first possible ' + 'occasion\n' + ' (either in a function that is called or on the next line in ' + 'the\n' + ' current function).\n' + '\n' + 'n(ext)\n' + '\n' + ' Continue execution until the next line in the current ' + 'function is\n' + ' reached or it returns. (The difference between "next" and ' + '"step"\n' + ' is that "step" stops inside a called function, while "next"\n' + ' executes called functions at (nearly) full speed, only ' + 'stopping at\n' + ' the next line in the current function.)\n' + '\n' + 'unt(il) [lineno]\n' + '\n' + ' Without argument, continue execution until the line with a ' + 'number\n' + ' greater than the current one is reached.\n' + '\n' + ' With *lineno*, continue execution until a line with a number\n' + ' greater or equal to *lineno* is reached. In both cases, also ' + 'stop\n' + ' when the current frame returns.\n' + '\n' + ' Changed in version 3.2: Allow giving an explicit line ' + 'number.\n' + '\n' + 'r(eturn)\n' + '\n' + ' Continue execution until the current function returns.\n' + '\n' + 'c(ont(inue))\n' + '\n' + ' Continue execution, only stop when a breakpoint is ' + 'encountered.\n' + '\n' + 'j(ump) lineno\n' + '\n' + ' Set the next line that will be executed. Only available in ' + 'the\n' + ' bottom-most frame. This lets you jump back and execute code ' + 'again,\n' + ' or jump forward to skip code that you don’t want to run.\n' + '\n' + ' It should be noted that not all jumps are allowed – for ' + 'instance it\n' + ' is not possible to jump into the middle of a "for" loop or ' + 'out of a\n' + ' "finally" clause.\n' + '\n' + 'l(ist) [first[, last]]\n' + '\n' + ' List source code for the current file. Without arguments, ' + 'list 11\n' + ' lines around the current line or continue the previous ' + 'listing.\n' + ' With "." as argument, list 11 lines around the current line. ' + 'With\n' + ' one argument, list 11 lines around at that line. With two\n' + ' arguments, list the given range; if the second argument is ' + 'less\n' + ' than the first, it is interpreted as a count.\n' + '\n' + ' The current line in the current frame is indicated by "->". ' + 'If an\n' + ' exception is being debugged, the line where the exception ' + 'was\n' + ' originally raised or propagated is indicated by ">>", if it ' + 'differs\n' + ' from the current line.\n' + '\n' + ' Changed in version 3.2: Added the ">>" marker.\n' + '\n' + 'll | longlist\n' + '\n' + ' List all source code for the current function or frame.\n' + ' Interesting lines are marked as for "list".\n' + '\n' + ' Added in version 3.2.\n' + '\n' + 'a(rgs)\n' + '\n' + ' Print the arguments of the current function and their ' + 'current\n' + ' values.\n' + '\n' + 'p expression\n' + '\n' + ' Evaluate *expression* in the current context and print its ' + 'value.\n' + '\n' + ' Note:\n' + '\n' + ' "print()" can also be used, but is not a debugger command — ' + 'this\n' + ' executes the Python "print()" function.\n' + '\n' + 'pp expression\n' + '\n' + ' Like the "p" command, except the value of *expression* is ' + 'pretty-\n' + ' printed using the "pprint" module.\n' + '\n' + 'whatis expression\n' + '\n' + ' Print the type of *expression*.\n' + '\n' + 'source expression\n' + '\n' + ' Try to get source code of *expression* and display it.\n' + '\n' + ' Added in version 3.2.\n' + '\n' + 'display [expression]\n' + '\n' + ' Display the value of *expression* if it changed, each time\n' + ' execution stops in the current frame.\n' + '\n' + ' Without *expression*, list all display expressions for the ' + 'current\n' + ' frame.\n' + '\n' + ' Note:\n' + '\n' + ' Display evaluates *expression* and compares to the result ' + 'of the\n' + ' previous evaluation of *expression*, so when the result is\n' + ' mutable, display may not be able to pick up the changes.\n' + '\n' + ' Example:\n' + '\n' + ' lst = []\n' + ' breakpoint()\n' + ' pass\n' + ' lst.append(1)\n' + ' print(lst)\n' + '\n' + ' Display won’t realize "lst" has been changed because the ' + 'result of\n' + ' evaluation is modified in place by "lst.append(1)" before ' + 'being\n' + ' compared:\n' + '\n' + ' > example.py(3)()\n' + ' -> pass\n' + ' (Pdb) display lst\n' + ' display lst: []\n' + ' (Pdb) n\n' + ' > example.py(4)()\n' + ' -> lst.append(1)\n' + ' (Pdb) n\n' + ' > example.py(5)()\n' + ' -> print(lst)\n' + ' (Pdb)\n' + '\n' + ' You can do some tricks with copy mechanism to make it work:\n' + '\n' + ' > example.py(3)()\n' + ' -> pass\n' + ' (Pdb) display lst[:]\n' + ' display lst[:]: []\n' + ' (Pdb) n\n' + ' > example.py(4)()\n' + ' -> lst.append(1)\n' + ' (Pdb) n\n' + ' > example.py(5)()\n' + ' -> print(lst)\n' + ' display lst[:]: [1] [old: []]\n' + ' (Pdb)\n' + '\n' + ' Added in version 3.2.\n' + '\n' + 'undisplay [expression]\n' + '\n' + ' Do not display *expression* anymore in the current frame. ' + 'Without\n' + ' *expression*, clear all display expressions for the current ' + 'frame.\n' + '\n' + ' Added in version 3.2.\n' + '\n' + 'interact\n' + '\n' + ' Start an interactive interpreter (using the "code" module) ' + 'whose\n' + ' global namespace contains all the (global and local) names ' + 'found in\n' + ' the current scope.\n' + '\n' + ' Added in version 3.2.\n' + '\n' + 'alias [name [command]]\n' + '\n' + ' Create an alias called *name* that executes *command*. The\n' + ' *command* must *not* be enclosed in quotes. Replaceable ' + 'parameters\n' + ' can be indicated by "%1", "%2", and so on, while "%*" is ' + 'replaced\n' + ' by all the parameters. If *command* is omitted, the current ' + 'alias\n' + ' for *name* is shown. If no arguments are given, all aliases ' + 'are\n' + ' listed.\n' + '\n' + ' Aliases may be nested and can contain anything that can be ' + 'legally\n' + ' typed at the pdb prompt. Note that internal pdb commands ' + '*can* be\n' + ' overridden by aliases. Such a command is then hidden until ' + 'the\n' + ' alias is removed. Aliasing is recursively applied to the ' + 'first\n' + ' word of the command line; all other words in the line are ' + 'left\n' + ' alone.\n' + '\n' + ' As an example, here are two useful aliases (especially when ' + 'placed\n' + ' in the ".pdbrc" file):\n' + '\n' + ' # Print instance variables (usage "pi classInst")\n' + ' alias pi for k in %1.__dict__.keys(): print(f"%1.{k} = ' + '{%1.__dict__[k]}")\n' + ' # Print instance variables in self\n' + ' alias ps pi self\n' + '\n' + 'unalias name\n' + '\n' + ' Delete the specified alias *name*.\n' + '\n' + '! statement\n' + '\n' + ' Execute the (one-line) *statement* in the context of the ' + 'current\n' + ' stack frame. The exclamation point can be omitted unless the ' + 'first\n' + ' word of the statement resembles a debugger command, e.g.:\n' + '\n' + ' (Pdb) ! n=42\n' + ' (Pdb)\n' + '\n' + ' To set a global variable, you can prefix the assignment ' + 'command\n' + ' with a "global" statement on the same line, e.g.:\n' + '\n' + " (Pdb) global list_options; list_options = ['-l']\n" + ' (Pdb)\n' + '\n' + 'run [args ...]\n' + 'restart [args ...]\n' + '\n' + ' Restart the debugged Python program. If *args* is supplied, ' + 'it is\n' + ' split with "shlex" and the result is used as the new ' + '"sys.argv".\n' + ' History, breakpoints, actions and debugger options are ' + 'preserved.\n' + ' "restart" is an alias for "run".\n' + '\n' + 'q(uit)\n' + '\n' + ' Quit from the debugger. The program being executed is ' + 'aborted.\n' + '\n' + 'debug code\n' + '\n' + ' Enter a recursive debugger that steps through *code* (which ' + 'is an\n' + ' arbitrary expression or statement to be executed in the ' + 'current\n' + ' environment).\n' + '\n' + 'retval\n' + '\n' + ' Print the return value for the last return of the current ' + 'function.\n' + '\n' + '-[ Footnotes ]-\n' + '\n' + '[1] Whether a frame is considered to originate in a certain ' + 'module is\n' + ' determined by the "__name__" in the frame globals.\n', + 'del': 'The "del" statement\n' + '*******************\n' '\n' - 'The following methods are used to override the default ' - 'behavior of the\n' - '"isinstance()" and "issubclass()" built-in functions.\n' + ' del_stmt ::= "del" target_list\n' '\n' - 'In particular, the metaclass "abc.ABCMeta" implements these ' - 'methods in\n' - 'order to allow the addition of Abstract Base Classes (ABCs) ' - 'as\n' - '“virtual base classes” to any class or type (including ' - 'built-in\n' - 'types), including other ABCs.\n' + 'Deletion is recursively defined very similar to the way assignment ' + 'is\n' + 'defined. Rather than spelling it out in full details, here are some\n' + 'hints.\n' '\n' - 'class.__instancecheck__(self, instance)\n' + 'Deletion of a target list recursively deletes each target, from left\n' + 'to right.\n' '\n' - ' Return true if *instance* should be considered a (direct ' + 'Deletion of a name removes the binding of that name from the local ' 'or\n' - ' indirect) instance of *class*. If defined, called to ' - 'implement\n' - ' "isinstance(instance, class)".\n' - '\n' - 'class.__subclasscheck__(self, subclass)\n' + 'global namespace, depending on whether the name occurs in a "global"\n' + 'statement in the same code block. If the name is unbound, a\n' + '"NameError" exception will be raised.\n' + '\n' + 'Deletion of attribute references, subscriptions and slicings is ' + 'passed\n' + 'to the primary object involved; deletion of a slicing is in general\n' + 'equivalent to assignment of an empty slice of the right type (but ' + 'even\n' + 'this is determined by the sliced object).\n' + '\n' + 'Changed in version 3.2: Previously it was illegal to delete a name\n' + 'from the local namespace if it occurs as a free variable in a nested\n' + 'block.\n', + 'dict': 'Dictionary displays\n' + '*******************\n' + '\n' + 'A dictionary display is a possibly empty series of dict items\n' + '(key/value pairs) enclosed in curly braces:\n' + '\n' + ' dict_display ::= "{" [dict_item_list | dict_comprehension] ' + '"}"\n' + ' dict_item_list ::= dict_item ("," dict_item)* [","]\n' + ' dict_item ::= expression ":" expression | "**" or_expr\n' + ' dict_comprehension ::= expression ":" expression comp_for\n' + '\n' + 'A dictionary display yields a new dictionary object.\n' + '\n' + 'If a comma-separated sequence of dict items is given, they are\n' + 'evaluated from left to right to define the entries of the ' + 'dictionary:\n' + 'each key object is used as a key into the dictionary to store the\n' + 'corresponding value. This means that you can specify the same key\n' + 'multiple times in the dict item list, and the final dictionary’s ' + 'value\n' + 'for that key will be the last one given.\n' + '\n' + 'A double asterisk "**" denotes *dictionary unpacking*. Its operand\n' + 'must be a *mapping*. Each mapping item is added to the new\n' + 'dictionary. Later values replace values already set by earlier ' + 'dict\n' + 'items and earlier dictionary unpackings.\n' + '\n' + 'Added in version 3.5: Unpacking into dictionary displays, ' + 'originally\n' + 'proposed by **PEP 448**.\n' + '\n' + 'A dict comprehension, in contrast to list and set comprehensions,\n' + 'needs two expressions separated with a colon followed by the usual\n' + '“for” and “if” clauses. When the comprehension is run, the ' + 'resulting\n' + 'key and value elements are inserted in the new dictionary in the ' + 'order\n' + 'they are produced.\n' + '\n' + 'Restrictions on the types of the key values are listed earlier in\n' + 'section The standard type hierarchy. (To summarize, the key type\n' + 'should be *hashable*, which excludes all mutable objects.) Clashes\n' + 'between duplicate keys are not detected; the last value (textually\n' + 'rightmost in the display) stored for a given key value prevails.\n' + '\n' + 'Changed in version 3.8: Prior to Python 3.8, in dict ' + 'comprehensions,\n' + 'the evaluation order of key and value was not well-defined. In\n' + 'CPython, the value was evaluated before the key. Starting with ' + '3.8,\n' + 'the key is evaluated before the value, as proposed by **PEP 572**.\n', + 'dynamic-features': 'Interaction with dynamic features\n' + '*********************************\n' + '\n' + 'Name resolution of free variables occurs at runtime, not ' + 'at compile\n' + 'time. This means that the following code will print 42:\n' + '\n' + ' i = 10\n' + ' def f():\n' + ' print(i)\n' + ' i = 42\n' + ' f()\n' + '\n' + 'The "eval()" and "exec()" functions do not have access ' + 'to the full\n' + 'environment for resolving names. Names may be resolved ' + 'in the local\n' + 'and global namespaces of the caller. Free variables are ' + 'not resolved\n' + 'in the nearest enclosing namespace, but in the global ' + 'namespace. [1]\n' + 'The "exec()" and "eval()" functions have optional ' + 'arguments to\n' + 'override the global and local namespace. If only one ' + 'namespace is\n' + 'specified, it is used for both.\n', + 'else': 'The "if" statement\n' + '******************\n' + '\n' + 'The "if" statement is used for conditional execution:\n' + '\n' + ' if_stmt ::= "if" assignment_expression ":" suite\n' + ' ("elif" assignment_expression ":" suite)*\n' + ' ["else" ":" suite]\n' + '\n' + 'It selects exactly one of the suites by evaluating the expressions ' + 'one\n' + 'by one until one is found to be true (see section Boolean ' + 'operations\n' + 'for the definition of true and false); then that suite is executed\n' + '(and no other part of the "if" statement is executed or evaluated).\n' + 'If all expressions are false, the suite of the "else" clause, if\n' + 'present, is executed.\n', + 'exceptions': 'Exceptions\n' + '**********\n' + '\n' + 'Exceptions are a means of breaking out of the normal flow of ' + 'control\n' + 'of a code block in order to handle errors or other ' + 'exceptional\n' + 'conditions. An exception is *raised* at the point where the ' + 'error is\n' + 'detected; it may be *handled* by the surrounding code block or ' + 'by any\n' + 'code block that directly or indirectly invoked the code block ' + 'where\n' + 'the error occurred.\n' + '\n' + 'The Python interpreter raises an exception when it detects a ' + 'run-time\n' + 'error (such as division by zero). A Python program can also\n' + 'explicitly raise an exception with the "raise" statement. ' + 'Exception\n' + 'handlers are specified with the "try" … "except" statement. ' + 'The\n' + '"finally" clause of such a statement can be used to specify ' + 'cleanup\n' + 'code which does not handle the exception, but is executed ' + 'whether an\n' + 'exception occurred or not in the preceding code.\n' + '\n' + 'Python uses the “termination” model of error handling: an ' + 'exception\n' + 'handler can find out what happened and continue execution at ' + 'an outer\n' + 'level, but it cannot repair the cause of the error and retry ' + 'the\n' + 'failing operation (except by re-entering the offending piece ' + 'of code\n' + 'from the top).\n' + '\n' + 'When an exception is not handled at all, the interpreter ' + 'terminates\n' + 'execution of the program, or returns to its interactive main ' + 'loop. In\n' + 'either case, it prints a stack traceback, except when the ' + 'exception is\n' + '"SystemExit".\n' + '\n' + 'Exceptions are identified by class instances. The "except" ' + 'clause is\n' + 'selected depending on the class of the instance: it must ' + 'reference the\n' + 'class of the instance or a *non-virtual base class* thereof. ' + 'The\n' + 'instance can be received by the handler and can carry ' + 'additional\n' + 'information about the exceptional condition.\n' + '\n' + 'Note:\n' + '\n' + ' Exception messages are not part of the Python API. Their ' + 'contents\n' + ' may change from one version of Python to the next without ' + 'warning\n' + ' and should not be relied on by code which will run under ' + 'multiple\n' + ' versions of the interpreter.\n' + '\n' + 'See also the description of the "try" statement in section The ' + 'try\n' + 'statement and "raise" statement in section The raise ' + 'statement.\n' + '\n' + '-[ Footnotes ]-\n' + '\n' + '[1] This limitation occurs because the code that is executed ' + 'by these\n' + ' operations is not available at the time the module is ' + 'compiled.\n', + 'execmodel': 'Execution model\n' + '***************\n' + '\n' + '\n' + 'Structure of a program\n' + '======================\n' + '\n' + 'A Python program is constructed from code blocks. A *block* is ' + 'a piece\n' + 'of Python program text that is executed as a unit. The ' + 'following are\n' + 'blocks: a module, a function body, and a class definition. ' + 'Each\n' + 'command typed interactively is a block. A script file (a file ' + 'given\n' + 'as standard input to the interpreter or specified as a command ' + 'line\n' + 'argument to the interpreter) is a code block. A script command ' + '(a\n' + 'command specified on the interpreter command line with the ' + '"-c"\n' + 'option) is a code block. A module run as a top level script (as ' + 'module\n' + '"__main__") from the command line using a "-m" argument is also ' + 'a code\n' + 'block. The string argument passed to the built-in functions ' + '"eval()"\n' + 'and "exec()" is a code block.\n' + '\n' + 'A code block is executed in an *execution frame*. A frame ' + 'contains\n' + 'some administrative information (used for debugging) and ' + 'determines\n' + 'where and how execution continues after the code block’s ' + 'execution has\n' + 'completed.\n' + '\n' + '\n' + 'Naming and binding\n' + '==================\n' + '\n' + '\n' + 'Binding of names\n' + '----------------\n' + '\n' + '*Names* refer to objects. Names are introduced by name ' + 'binding\n' + 'operations.\n' + '\n' + 'The following constructs bind names:\n' + '\n' + '* formal parameters to functions,\n' + '\n' + '* class definitions,\n' + '\n' + '* function definitions,\n' + '\n' + '* assignment expressions,\n' + '\n' + '* targets that are identifiers if occurring in an assignment:\n' + '\n' + ' * "for" loop header,\n' + '\n' + ' * after "as" in a "with" statement, "except" clause, ' + '"except*"\n' + ' clause, or in the as-pattern in structural pattern ' + 'matching,\n' + '\n' + ' * in a capture pattern in structural pattern matching\n' + '\n' + '* "import" statements.\n' + '\n' + '* "type" statements.\n' + '\n' + '* type parameter lists.\n' + '\n' + 'The "import" statement of the form "from ... import *" binds ' + 'all names\n' + 'defined in the imported module, except those beginning with an\n' + 'underscore. This form may only be used at the module level.\n' + '\n' + 'A target occurring in a "del" statement is also considered ' + 'bound for\n' + 'this purpose (though the actual semantics are to unbind the ' + 'name).\n' + '\n' + 'Each assignment or import statement occurs within a block ' + 'defined by a\n' + 'class or function definition or at the module level (the ' + 'top-level\n' + 'code block).\n' + '\n' + 'If a name is bound in a block, it is a local variable of that ' + 'block,\n' + 'unless declared as "nonlocal" or "global". If a name is bound ' + 'at the\n' + 'module level, it is a global variable. (The variables of the ' + 'module\n' + 'code block are local and global.) If a variable is used in a ' + 'code\n' + 'block but not defined there, it is a *free variable*.\n' + '\n' + 'Each occurrence of a name in the program text refers to the ' + '*binding*\n' + 'of that name established by the following name resolution ' + 'rules.\n' + '\n' + '\n' + 'Resolution of names\n' + '-------------------\n' + '\n' + 'A *scope* defines the visibility of a name within a block. If ' + 'a local\n' + 'variable is defined in a block, its scope includes that block. ' + 'If the\n' + 'definition occurs in a function block, the scope extends to any ' + 'blocks\n' + 'contained within the defining one, unless a contained block ' + 'introduces\n' + 'a different binding for the name.\n' + '\n' + 'When a name is used in a code block, it is resolved using the ' + 'nearest\n' + 'enclosing scope. The set of all such scopes visible to a code ' + 'block\n' + 'is called the block’s *environment*.\n' + '\n' + 'When a name is not found at all, a "NameError" exception is ' + 'raised. If\n' + 'the current scope is a function scope, and the name refers to a ' + 'local\n' + 'variable that has not yet been bound to a value at the point ' + 'where the\n' + 'name is used, an "UnboundLocalError" exception is raised.\n' + '"UnboundLocalError" is a subclass of "NameError".\n' + '\n' + 'If a name binding operation occurs anywhere within a code ' + 'block, all\n' + 'uses of the name within the block are treated as references to ' + 'the\n' + 'current block. This can lead to errors when a name is used ' + 'within a\n' + 'block before it is bound. This rule is subtle. Python lacks\n' + 'declarations and allows name binding operations to occur ' + 'anywhere\n' + 'within a code block. The local variables of a code block can ' + 'be\n' + 'determined by scanning the entire text of the block for name ' + 'binding\n' + 'operations. See the FAQ entry on UnboundLocalError for ' + 'examples.\n' + '\n' + 'If the "global" statement occurs within a block, all uses of ' + 'the names\n' + 'specified in the statement refer to the bindings of those names ' + 'in the\n' + 'top-level namespace. Names are resolved in the top-level ' + 'namespace by\n' + 'searching the global namespace, i.e. the namespace of the ' + 'module\n' + 'containing the code block, and the builtins namespace, the ' + 'namespace\n' + 'of the module "builtins". The global namespace is searched ' + 'first. If\n' + 'the names are not found there, the builtins namespace is ' + 'searched\n' + 'next. If the names are also not found in the builtins ' + 'namespace, new\n' + 'variables are created in the global namespace. The global ' + 'statement\n' + 'must precede all uses of the listed names.\n' + '\n' + 'The "global" statement has the same scope as a name binding ' + 'operation\n' + 'in the same block. If the nearest enclosing scope for a free ' + 'variable\n' + 'contains a global statement, the free variable is treated as a ' + 'global.\n' + '\n' + 'The "nonlocal" statement causes corresponding names to refer ' + 'to\n' + 'previously bound variables in the nearest enclosing function ' + 'scope.\n' + '"SyntaxError" is raised at compile time if the given name does ' + 'not\n' + 'exist in any enclosing function scope. Type parameters cannot ' + 'be\n' + 'rebound with the "nonlocal" statement.\n' + '\n' + 'The namespace for a module is automatically created the first ' + 'time a\n' + 'module is imported. The main module for a script is always ' + 'called\n' + '"__main__".\n' + '\n' + 'Class definition blocks and arguments to "exec()" and "eval()" ' + 'are\n' + 'special in the context of name resolution. A class definition ' + 'is an\n' + 'executable statement that may use and define names. These ' + 'references\n' + 'follow the normal rules for name resolution with an exception ' + 'that\n' + 'unbound local variables are looked up in the global namespace. ' + 'The\n' + 'namespace of the class definition becomes the attribute ' + 'dictionary of\n' + 'the class. The scope of names defined in a class block is ' + 'limited to\n' + 'the class block; it does not extend to the code blocks of ' + 'methods.\n' + 'This includes comprehensions and generator expressions, but it ' + 'does\n' + 'not include annotation scopes, which have access to their ' + 'enclosing\n' + 'class scopes. This means that the following will fail:\n' + '\n' + ' class A:\n' + ' a = 42\n' + ' b = list(a + i for i in range(10))\n' + '\n' + 'However, the following will succeed:\n' + '\n' + ' class A:\n' + ' type Alias = Nested\n' + ' class Nested: pass\n' + '\n' + " print(A.Alias.__value__) # \n" + '\n' + '\n' + 'Annotation scopes\n' + '-----------------\n' + '\n' + 'Type parameter lists and "type" statements introduce ' + '*annotation\n' + 'scopes*, which behave mostly like function scopes, but with ' + 'some\n' + 'exceptions discussed below. *Annotations* currently do not use\n' + 'annotation scopes, but they are expected to use annotation ' + 'scopes in\n' + 'Python 3.13 when **PEP 649** is implemented.\n' + '\n' + 'Annotation scopes are used in the following contexts:\n' + '\n' + '* Type parameter lists for generic type aliases.\n' + '\n' + '* Type parameter lists for generic functions. A generic ' + 'function’s\n' + ' annotations are executed within the annotation scope, but ' + 'its\n' + ' defaults and decorators are not.\n' + '\n' + '* Type parameter lists for generic classes. A generic class’s ' + 'base\n' + ' classes and keyword arguments are executed within the ' + 'annotation\n' + ' scope, but its decorators are not.\n' + '\n' + '* The bounds and constraints for type variables (lazily ' + 'evaluated).\n' + '\n' + '* The value of type aliases (lazily evaluated).\n' + '\n' + 'Annotation scopes differ from function scopes in the following ' + 'ways:\n' + '\n' + '* Annotation scopes have access to their enclosing class ' + 'namespace. If\n' + ' an annotation scope is immediately within a class scope, or ' + 'within\n' + ' another annotation scope that is immediately within a class ' + 'scope,\n' + ' the code in the annotation scope can use names defined in the ' + 'class\n' + ' scope as if it were executed directly within the class body. ' + 'This\n' + ' contrasts with regular functions defined within classes, ' + 'which\n' + ' cannot access names defined in the class scope.\n' + '\n' + '* Expressions in annotation scopes cannot contain "yield", ' + '"yield\n' + ' from", "await", or ":=" expressions. (These expressions are ' + 'allowed\n' + ' in other scopes contained within the annotation scope.)\n' + '\n' + '* Names defined in annotation scopes cannot be rebound with ' + '"nonlocal"\n' + ' statements in inner scopes. This includes only type ' + 'parameters, as\n' + ' no other syntactic elements that can appear within annotation ' + 'scopes\n' + ' can introduce new names.\n' + '\n' + '* While annotation scopes have an internal name, that name is ' + 'not\n' + ' reflected in the *qualified name* of objects defined within ' + 'the\n' + ' scope. Instead, the "__qualname__" of such objects is as if ' + 'the\n' + ' object were defined in the enclosing scope.\n' + '\n' + 'Added in version 3.12: Annotation scopes were introduced in ' + 'Python\n' + '3.12 as part of **PEP 695**.\n' + '\n' + '\n' + 'Lazy evaluation\n' + '---------------\n' + '\n' + 'The values of type aliases created through the "type" statement ' + 'are\n' + '*lazily evaluated*. The same applies to the bounds and ' + 'constraints of\n' + 'type variables created through the type parameter syntax. This ' + 'means\n' + 'that they are not evaluated when the type alias or type ' + 'variable is\n' + 'created. Instead, they are only evaluated when doing so is ' + 'necessary\n' + 'to resolve an attribute access.\n' + '\n' + 'Example:\n' + '\n' + ' >>> type Alias = 1/0\n' + ' >>> Alias.__value__\n' + ' Traceback (most recent call last):\n' + ' ...\n' + ' ZeroDivisionError: division by zero\n' + ' >>> def func[T: 1/0](): pass\n' + ' >>> T = func.__type_params__[0]\n' + ' >>> T.__bound__\n' + ' Traceback (most recent call last):\n' + ' ...\n' + ' ZeroDivisionError: division by zero\n' + '\n' + 'Here the exception is raised only when the "__value__" ' + 'attribute of\n' + 'the type alias or the "__bound__" attribute of the type ' + 'variable is\n' + 'accessed.\n' + '\n' + 'This behavior is primarily useful for references to types that ' + 'have\n' + 'not yet been defined when the type alias or type variable is ' + 'created.\n' + 'For example, lazy evaluation enables creation of mutually ' + 'recursive\n' + 'type aliases:\n' + '\n' + ' from typing import Literal\n' + '\n' + ' type SimpleExpr = int | Parenthesized\n' + ' type Parenthesized = tuple[Literal["("], Expr, ' + 'Literal[")"]]\n' + ' type Expr = SimpleExpr | tuple[SimpleExpr, Literal["+", ' + '"-"], Expr]\n' + '\n' + 'Lazily evaluated values are evaluated in annotation scope, ' + 'which means\n' + 'that names that appear inside the lazily evaluated value are ' + 'looked up\n' + 'as if they were used in the immediately enclosing scope.\n' + '\n' + 'Added in version 3.12.\n' + '\n' + '\n' + 'Builtins and restricted execution\n' + '---------------------------------\n' + '\n' + '**CPython implementation detail:** Users should not touch\n' + '"__builtins__"; it is strictly an implementation detail. ' + 'Users\n' + 'wanting to override values in the builtins namespace should ' + '"import"\n' + 'the "builtins" module and modify its attributes appropriately.\n' + '\n' + 'The builtins namespace associated with the execution of a code ' + 'block\n' + 'is actually found by looking up the name "__builtins__" in its ' + 'global\n' + 'namespace; this should be a dictionary or a module (in the ' + 'latter case\n' + 'the module’s dictionary is used). By default, when in the ' + '"__main__"\n' + 'module, "__builtins__" is the built-in module "builtins"; when ' + 'in any\n' + 'other module, "__builtins__" is an alias for the dictionary of ' + 'the\n' + '"builtins" module itself.\n' + '\n' + '\n' + 'Interaction with dynamic features\n' + '---------------------------------\n' + '\n' + 'Name resolution of free variables occurs at runtime, not at ' + 'compile\n' + 'time. This means that the following code will print 42:\n' + '\n' + ' i = 10\n' + ' def f():\n' + ' print(i)\n' + ' i = 42\n' + ' f()\n' + '\n' + 'The "eval()" and "exec()" functions do not have access to the ' + 'full\n' + 'environment for resolving names. Names may be resolved in the ' + 'local\n' + 'and global namespaces of the caller. Free variables are not ' + 'resolved\n' + 'in the nearest enclosing namespace, but in the global ' + 'namespace. [1]\n' + 'The "exec()" and "eval()" functions have optional arguments to\n' + 'override the global and local namespace. If only one namespace ' + 'is\n' + 'specified, it is used for both.\n' + '\n' + '\n' + 'Exceptions\n' + '==========\n' + '\n' + 'Exceptions are a means of breaking out of the normal flow of ' + 'control\n' + 'of a code block in order to handle errors or other exceptional\n' + 'conditions. An exception is *raised* at the point where the ' + 'error is\n' + 'detected; it may be *handled* by the surrounding code block or ' + 'by any\n' + 'code block that directly or indirectly invoked the code block ' + 'where\n' + 'the error occurred.\n' + '\n' + 'The Python interpreter raises an exception when it detects a ' + 'run-time\n' + 'error (such as division by zero). A Python program can also\n' + 'explicitly raise an exception with the "raise" statement. ' + 'Exception\n' + 'handlers are specified with the "try" … "except" statement. ' + 'The\n' + '"finally" clause of such a statement can be used to specify ' + 'cleanup\n' + 'code which does not handle the exception, but is executed ' + 'whether an\n' + 'exception occurred or not in the preceding code.\n' + '\n' + 'Python uses the “termination” model of error handling: an ' + 'exception\n' + 'handler can find out what happened and continue execution at an ' + 'outer\n' + 'level, but it cannot repair the cause of the error and retry ' + 'the\n' + 'failing operation (except by re-entering the offending piece of ' + 'code\n' + 'from the top).\n' + '\n' + 'When an exception is not handled at all, the interpreter ' + 'terminates\n' + 'execution of the program, or returns to its interactive main ' + 'loop. In\n' + 'either case, it prints a stack traceback, except when the ' + 'exception is\n' + '"SystemExit".\n' + '\n' + 'Exceptions are identified by class instances. The "except" ' + 'clause is\n' + 'selected depending on the class of the instance: it must ' + 'reference the\n' + 'class of the instance or a *non-virtual base class* thereof. ' + 'The\n' + 'instance can be received by the handler and can carry ' + 'additional\n' + 'information about the exceptional condition.\n' + '\n' + 'Note:\n' + '\n' + ' Exception messages are not part of the Python API. Their ' + 'contents\n' + ' may change from one version of Python to the next without ' + 'warning\n' + ' and should not be relied on by code which will run under ' + 'multiple\n' + ' versions of the interpreter.\n' + '\n' + 'See also the description of the "try" statement in section The ' + 'try\n' + 'statement and "raise" statement in section The raise ' + 'statement.\n' + '\n' + '-[ Footnotes ]-\n' + '\n' + '[1] This limitation occurs because the code that is executed by ' + 'these\n' + ' operations is not available at the time the module is ' + 'compiled.\n', + 'exprlists': 'Expression lists\n' + '****************\n' + '\n' + ' starred_expression ::= ["*"] or_expr\n' + ' flexible_expression ::= assignment_expression | ' + 'starred_expression\n' + ' flexible_expression_list ::= flexible_expression ("," ' + 'flexible_expression)* [","]\n' + ' starred_expression_list ::= starred_expression ("," ' + 'starred_expression)* [","]\n' + ' expression_list ::= expression ("," expression)* ' + '[","]\n' + ' yield_list ::= expression_list | ' + 'starred_expression "," [starred_expression_list]\n' + '\n' + 'Except when part of a list or set display, an expression list\n' + 'containing at least one comma yields a tuple. The length of ' + 'the tuple\n' + 'is the number of expressions in the list. The expressions are\n' + 'evaluated from left to right.\n' + '\n' + 'An asterisk "*" denotes *iterable unpacking*. Its operand must ' + 'be an\n' + '*iterable*. The iterable is expanded into a sequence of items, ' + 'which\n' + 'are included in the new tuple, list, or set, at the site of ' + 'the\n' + 'unpacking.\n' + '\n' + 'Added in version 3.5: Iterable unpacking in expression lists,\n' + 'originally proposed by **PEP 448**.\n' + '\n' + 'Added in version 3.11: Any item in an expression list may be ' + 'starred.\n' + 'See **PEP 646**.\n' + '\n' + 'A trailing comma is required only to create a one-item tuple, ' + 'such as\n' + '"1,"; it is optional in all other cases. A single expression ' + 'without a\n' + 'trailing comma doesn’t create a tuple, but rather yields the ' + 'value of\n' + 'that expression. (To create an empty tuple, use an empty pair ' + 'of\n' + 'parentheses: "()".)\n', + 'floating': 'Floating-point literals\n' + '***********************\n' + '\n' + 'Floating-point literals are described by the following lexical\n' + 'definitions:\n' + '\n' + ' floatnumber ::= pointfloat | exponentfloat\n' + ' pointfloat ::= [digitpart] fraction | digitpart "."\n' + ' exponentfloat ::= (digitpart | pointfloat) exponent\n' + ' digitpart ::= digit (["_"] digit)*\n' + ' fraction ::= "." digitpart\n' + ' exponent ::= ("e" | "E") ["+" | "-"] digitpart\n' + '\n' + 'Note that the integer and exponent parts are always interpreted ' + 'using\n' + 'radix 10. For example, "077e010" is legal, and denotes the same ' + 'number\n' + 'as "77e10". The allowed range of floating-point literals is\n' + 'implementation-dependent. As in integer literals, underscores ' + 'are\n' + 'supported for digit grouping.\n' + '\n' + 'Some examples of floating-point literals:\n' + '\n' + ' 3.14 10. .001 1e100 3.14e-10 0e0 ' + '3.14_15_93\n' + '\n' + 'Changed in version 3.6: Underscores are now allowed for ' + 'grouping\n' + 'purposes in literals.\n', + 'for': 'The "for" statement\n' + '*******************\n' '\n' - ' Return true if *subclass* should be considered a (direct ' + 'The "for" statement is used to iterate over the elements of a ' + 'sequence\n' + '(such as a string, tuple or list) or other iterable object:\n' + '\n' + ' for_stmt ::= "for" target_list "in" starred_list ":" suite\n' + ' ["else" ":" suite]\n' + '\n' + 'The "starred_list" expression is evaluated once; it should yield an\n' + '*iterable* object. An *iterator* is created for that iterable. The\n' + 'first item provided by the iterator is then assigned to the target\n' + 'list using the standard rules for assignments (see Assignment\n' + 'statements), and the suite is executed. This repeats for each item\n' + 'provided by the iterator. When the iterator is exhausted, the suite\n' + 'in the "else" clause, if present, is executed, and the loop\n' + 'terminates.\n' + '\n' + 'A "break" statement executed in the first suite terminates the loop\n' + 'without executing the "else" clause’s suite. A "continue" statement\n' + 'executed in the first suite skips the rest of the suite and ' + 'continues\n' + 'with the next item, or with the "else" clause if there is no next\n' + 'item.\n' + '\n' + 'The for-loop makes assignments to the variables in the target list.\n' + 'This overwrites all previous assignments to those variables ' + 'including\n' + 'those made in the suite of the for-loop:\n' + '\n' + ' for i in range(10):\n' + ' print(i)\n' + ' i = 5 # this will not affect the for-loop\n' + ' # because i will be overwritten with the ' + 'next\n' + ' # index in the range\n' + '\n' + 'Names in the target list are not deleted when the loop is finished,\n' + 'but if the sequence is empty, they will not have been assigned to at\n' + 'all by the loop. Hint: the built-in type "range()" represents\n' + 'immutable arithmetic sequences of integers. For instance, iterating\n' + '"range(3)" successively yields 0, 1, and then 2.\n' + '\n' + 'Changed in version 3.11: Starred elements are now allowed in the\n' + 'expression list.\n', + 'formatstrings': 'Format String Syntax\n' + '********************\n' + '\n' + 'The "str.format()" method and the "Formatter" class share ' + 'the same\n' + 'syntax for format strings (although in the case of ' + '"Formatter",\n' + 'subclasses can define their own format string syntax). The ' + 'syntax is\n' + 'related to that of formatted string literals, but it is ' + 'less\n' + 'sophisticated and, in particular, does not support ' + 'arbitrary\n' + 'expressions.\n' + '\n' + 'Format strings contain “replacement fields” surrounded by ' + 'curly braces\n' + '"{}". Anything that is not contained in braces is ' + 'considered literal\n' + 'text, which is copied unchanged to the output. If you need ' + 'to include\n' + 'a brace character in the literal text, it can be escaped by ' + 'doubling:\n' + '"{{" and "}}".\n' + '\n' + 'The grammar for a replacement field is as follows:\n' + '\n' + ' replacement_field ::= "{" [field_name] ["!" conversion] ' + '[":" format_spec] "}"\n' + ' field_name ::= arg_name ("." attribute_name | "[" ' + 'element_index "]")*\n' + ' arg_name ::= [identifier | digit+]\n' + ' attribute_name ::= identifier\n' + ' element_index ::= digit+ | index_string\n' + ' index_string ::= ' + '+\n' + ' conversion ::= "r" | "s" | "a"\n' + ' format_spec ::= format-spec:format_spec\n' + '\n' + 'In less formal terms, the replacement field can start with ' + 'a\n' + '*field_name* that specifies the object whose value is to be ' + 'formatted\n' + 'and inserted into the output instead of the replacement ' + 'field. The\n' + '*field_name* is optionally followed by a *conversion* ' + 'field, which is\n' + 'preceded by an exclamation point "\'!\'", and a ' + '*format_spec*, which is\n' + 'preceded by a colon "\':\'". These specify a non-default ' + 'format for the\n' + 'replacement value.\n' + '\n' + 'See also the Format Specification Mini-Language section.\n' + '\n' + 'The *field_name* itself begins with an *arg_name* that is ' + 'either a\n' + 'number or a keyword. If it’s a number, it refers to a ' + 'positional\n' + 'argument, and if it’s a keyword, it refers to a named ' + 'keyword\n' + 'argument. An *arg_name* is treated as a number if a call ' + 'to\n' + '"str.isdecimal()" on the string would return true. If the ' + 'numerical\n' + 'arg_names in a format string are 0, 1, 2, … in sequence, ' + 'they can all\n' + 'be omitted (not just some) and the numbers 0, 1, 2, … will ' + 'be\n' + 'automatically inserted in that order. Because *arg_name* is ' + 'not quote-\n' + 'delimited, it is not possible to specify arbitrary ' + 'dictionary keys\n' + '(e.g., the strings "\'10\'" or "\':-]\'") within a format ' + 'string. The\n' + '*arg_name* can be followed by any number of index or ' + 'attribute\n' + 'expressions. An expression of the form "\'.name\'" selects ' + 'the named\n' + 'attribute using "getattr()", while an expression of the ' + 'form\n' + '"\'[index]\'" does an index lookup using "__getitem__()".\n' + '\n' + 'Changed in version 3.1: The positional argument specifiers ' + 'can be\n' + 'omitted for "str.format()", so "\'{} {}\'.format(a, b)" is ' + 'equivalent to\n' + '"\'{0} {1}\'.format(a, b)".\n' + '\n' + 'Changed in version 3.4: The positional argument specifiers ' + 'can be\n' + 'omitted for "Formatter".\n' + '\n' + 'Some simple format string examples:\n' + '\n' + ' "First, thou shalt count to {0}" # References first ' + 'positional argument\n' + ' "Bring me a {}" # Implicitly ' + 'references the first positional argument\n' + ' "From {} to {}" # Same as "From {0} to ' + '{1}"\n' + ' "My quest is {name}" # References keyword ' + "argument 'name'\n" + ' "Weight in tons {0.weight}" # \'weight\' attribute ' + 'of first positional arg\n' + ' "Units destroyed: {players[0]}" # First element of ' + "keyword argument 'players'.\n" + '\n' + 'The *conversion* field causes a type coercion before ' + 'formatting.\n' + 'Normally, the job of formatting a value is done by the ' + '"__format__()"\n' + 'method of the value itself. However, in some cases it is ' + 'desirable to\n' + 'force a type to be formatted as a string, overriding its ' + 'own\n' + 'definition of formatting. By converting the value to a ' + 'string before\n' + 'calling "__format__()", the normal formatting logic is ' + 'bypassed.\n' + '\n' + 'Three conversion flags are currently supported: "\'!s\'" ' + 'which calls\n' + '"str()" on the value, "\'!r\'" which calls "repr()" and ' + '"\'!a\'" which\n' + 'calls "ascii()".\n' + '\n' + 'Some examples:\n' + '\n' + ' "Harold\'s a clever {0!s}" # Calls str() on the ' + 'argument first\n' + ' "Bring out the holy {name!r}" # Calls repr() on the ' + 'argument first\n' + ' "More {!a}" # Calls ascii() on the ' + 'argument first\n' + '\n' + 'The *format_spec* field contains a specification of how the ' + 'value\n' + 'should be presented, including such details as field width, ' + 'alignment,\n' + 'padding, decimal precision and so on. Each value type can ' + 'define its\n' + 'own “formatting mini-language” or interpretation of the ' + '*format_spec*.\n' + '\n' + 'Most built-in types support a common formatting ' + 'mini-language, which\n' + 'is described in the next section.\n' + '\n' + 'A *format_spec* field can also include nested replacement ' + 'fields\n' + 'within it. These nested replacement fields may contain a ' + 'field name,\n' + 'conversion flag and format specification, but deeper ' + 'nesting is not\n' + 'allowed. The replacement fields within the format_spec ' + 'are\n' + 'substituted before the *format_spec* string is interpreted. ' + 'This\n' + 'allows the formatting of a value to be dynamically ' + 'specified.\n' + '\n' + 'See the Format examples section for some examples.\n' + '\n' + '\n' + 'Format Specification Mini-Language\n' + '==================================\n' + '\n' + '“Format specifications” are used within replacement fields ' + 'contained\n' + 'within a format string to define how individual values are ' + 'presented\n' + '(see Format String Syntax and f-strings). They can also be ' + 'passed\n' + 'directly to the built-in "format()" function. Each ' + 'formattable type\n' + 'may define how the format specification is to be ' + 'interpreted.\n' + '\n' + 'Most built-in types implement the following options for ' + 'format\n' + 'specifications, although some of the formatting options are ' + 'only\n' + 'supported by the numeric types.\n' + '\n' + 'A general convention is that an empty format specification ' + 'produces\n' + 'the same result as if you had called "str()" on the value. ' + 'A non-empty\n' + 'format specification typically modifies the result.\n' + '\n' + 'The general form of a *standard format specifier* is:\n' + '\n' + ' format_spec ::= ' + '[[fill]align][sign]["z"]["#"]["0"][width][grouping_option]["." ' + 'precision][type]\n' + ' fill ::= \n' + ' align ::= "<" | ">" | "=" | "^"\n' + ' sign ::= "+" | "-" | " "\n' + ' width ::= digit+\n' + ' grouping_option ::= "_" | ","\n' + ' precision ::= digit+\n' + ' type ::= "b" | "c" | "d" | "e" | "E" | "f" | ' + '"F" | "g" | "G" | "n" | "o" | "s" | "x" | "X" | "%"\n' + '\n' + 'If a valid *align* value is specified, it can be preceded ' + 'by a *fill*\n' + 'character that can be any character and defaults to a space ' + 'if\n' + 'omitted. It is not possible to use a literal curly brace ' + '(”"{"” or\n' + '“"}"”) as the *fill* character in a formatted string ' + 'literal or when\n' + 'using the "str.format()" method. However, it is possible ' + 'to insert a\n' + 'curly brace with a nested replacement field. This ' + 'limitation doesn’t\n' + 'affect the "format()" function.\n' + '\n' + 'The meaning of the various alignment options is as ' + 'follows:\n' + '\n' + '+-----------+------------------------------------------------------------+\n' + '| Option | ' + 'Meaning ' + '|\n' + '|===========|============================================================|\n' + '| "\'<\'" | Forces the field to be left-aligned within ' + 'the available |\n' + '| | space (this is the default for most ' + 'objects). |\n' + '+-----------+------------------------------------------------------------+\n' + '| "\'>\'" | Forces the field to be right-aligned within ' + 'the available |\n' + '| | space (this is the default for ' + 'numbers). |\n' + '+-----------+------------------------------------------------------------+\n' + '| "\'=\'" | Forces the padding to be placed after the ' + 'sign (if any) |\n' + '| | but before the digits. This is used for ' + 'printing fields |\n' + '| | in the form ‘+000000120’. This alignment ' + 'option is only |\n' + '| | valid for numeric types, excluding "complex". ' + 'It becomes |\n' + '| | the default for numbers when ‘0’ immediately ' + 'precedes the |\n' + '| | field ' + 'width. |\n' + '+-----------+------------------------------------------------------------+\n' + '| "\'^\'" | Forces the field to be centered within the ' + 'available |\n' + '| | ' + 'space. ' + '|\n' + '+-----------+------------------------------------------------------------+\n' + '\n' + 'Note that unless a minimum field width is defined, the ' + 'field width\n' + 'will always be the same size as the data to fill it, so ' + 'that the\n' + 'alignment option has no meaning in this case.\n' + '\n' + 'The *sign* option is only valid for number types, and can ' + 'be one of\n' + 'the following:\n' + '\n' + '+-----------+------------------------------------------------------------+\n' + '| Option | ' + 'Meaning ' + '|\n' + '|===========|============================================================|\n' + '| "\'+\'" | indicates that a sign should be used for ' + 'both positive as |\n' + '| | well as negative ' + 'numbers. |\n' + '+-----------+------------------------------------------------------------+\n' + '| "\'-\'" | indicates that a sign should be used only ' + 'for negative |\n' + '| | numbers (this is the default ' + 'behavior). |\n' + '+-----------+------------------------------------------------------------+\n' + '| space | indicates that a leading space should be used ' + 'on positive |\n' + '| | numbers, and a minus sign on negative ' + 'numbers. |\n' + '+-----------+------------------------------------------------------------+\n' + '\n' + 'The "\'z\'" option coerces negative zero floating-point ' + 'values to\n' + 'positive zero after rounding to the format precision. This ' + 'option is\n' + 'only valid for floating-point presentation types.\n' + '\n' + 'Changed in version 3.11: Added the "\'z\'" option (see also ' + '**PEP\n' + '682**).\n' + '\n' + 'The "\'#\'" option causes the “alternate form” to be used ' + 'for the\n' + 'conversion. The alternate form is defined differently for ' + 'different\n' + 'types. This option is only valid for integer, float and ' + 'complex\n' + 'types. For integers, when binary, octal, or hexadecimal ' + 'output is\n' + 'used, this option adds the respective prefix "\'0b\'", ' + '"\'0o\'", "\'0x\'",\n' + 'or "\'0X\'" to the output value. For float and complex the ' + 'alternate\n' + 'form causes the result of the conversion to always contain ' + 'a decimal-\n' + 'point character, even if no digits follow it. Normally, a ' + 'decimal-\n' + 'point character appears in the result of these conversions ' + 'only if a\n' + 'digit follows it. In addition, for "\'g\'" and "\'G\'" ' + 'conversions,\n' + 'trailing zeros are not removed from the result.\n' + '\n' + 'The "\',\'" option signals the use of a comma for a ' + 'thousands separator.\n' + 'For a locale aware separator, use the "\'n\'" integer ' + 'presentation type\n' + 'instead.\n' + '\n' + 'Changed in version 3.1: Added the "\',\'" option (see also ' + '**PEP 378**).\n' + '\n' + 'The "\'_\'" option signals the use of an underscore for a ' + 'thousands\n' + 'separator for floating-point presentation types and for ' + 'integer\n' + 'presentation type "\'d\'". For integer presentation types ' + '"\'b\'", "\'o\'",\n' + '"\'x\'", and "\'X\'", underscores will be inserted every 4 ' + 'digits. For\n' + 'other presentation types, specifying this option is an ' + 'error.\n' + '\n' + 'Changed in version 3.6: Added the "\'_\'" option (see also ' + '**PEP 515**).\n' + '\n' + '*width* is a decimal integer defining the minimum total ' + 'field width,\n' + 'including any prefixes, separators, and other formatting ' + 'characters.\n' + 'If not specified, then the field width will be determined ' + 'by the\n' + 'content.\n' + '\n' + 'When no explicit alignment is given, preceding the *width* ' + 'field by a\n' + 'zero ("\'0\'") character enables sign-aware zero-padding ' + 'for numeric\n' + 'types, excluding "complex". This is equivalent to a *fill* ' + 'character\n' + 'of "\'0\'" with an *alignment* type of "\'=\'".\n' + '\n' + 'Changed in version 3.10: Preceding the *width* field by ' + '"\'0\'" no\n' + 'longer affects the default alignment for strings.\n' + '\n' + 'The *precision* is a decimal integer indicating how many ' + 'digits should\n' + 'be displayed after the decimal point for presentation types ' + '"\'f\'" and\n' + '"\'F\'", or before and after the decimal point for ' + 'presentation types\n' + '"\'g\'" or "\'G\'". For string presentation types the ' + 'field indicates the\n' + 'maximum field size - in other words, how many characters ' + 'will be used\n' + 'from the field content. The *precision* is not allowed for ' + 'integer\n' + 'presentation types.\n' + '\n' + 'Finally, the *type* determines how the data should be ' + 'presented.\n' + '\n' + 'The available string presentation types are:\n' + '\n' + ' ' + '+-----------+------------------------------------------------------------+\n' + ' | Type | ' + 'Meaning ' + '|\n' + ' ' + '|===========|============================================================|\n' + ' | "\'s\'" | String format. This is the default type ' + 'for strings and |\n' + ' | | may be ' + 'omitted. |\n' + ' ' + '+-----------+------------------------------------------------------------+\n' + ' | None | The same as ' + '"\'s\'". |\n' + ' ' + '+-----------+------------------------------------------------------------+\n' + '\n' + 'The available integer presentation types are:\n' + '\n' + ' ' + '+-----------+------------------------------------------------------------+\n' + ' | Type | ' + 'Meaning ' + '|\n' + ' ' + '|===========|============================================================|\n' + ' | "\'b\'" | Binary format. Outputs the number in ' + 'base 2. |\n' + ' ' + '+-----------+------------------------------------------------------------+\n' + ' | "\'c\'" | Character. Converts the integer to the ' + 'corresponding |\n' + ' | | unicode character before ' + 'printing. |\n' + ' ' + '+-----------+------------------------------------------------------------+\n' + ' | "\'d\'" | Decimal Integer. Outputs the number in ' + 'base 10. |\n' + ' ' + '+-----------+------------------------------------------------------------+\n' + ' | "\'o\'" | Octal format. Outputs the number in base ' + '8. |\n' + ' ' + '+-----------+------------------------------------------------------------+\n' + ' | "\'x\'" | Hex format. Outputs the number in base ' + '16, using lower- |\n' + ' | | case letters for the digits above ' + '9. |\n' + ' ' + '+-----------+------------------------------------------------------------+\n' + ' | "\'X\'" | Hex format. Outputs the number in base ' + '16, using upper- |\n' + ' | | case letters for the digits above 9. In ' + 'case "\'#\'" is |\n' + ' | | specified, the prefix "\'0x\'" will be ' + 'upper-cased to "\'0X\'" |\n' + ' | | as ' + 'well. |\n' + ' ' + '+-----------+------------------------------------------------------------+\n' + ' | "\'n\'" | Number. This is the same as "\'d\'", ' + 'except that it uses the |\n' + ' | | current locale setting to insert the ' + 'appropriate number |\n' + ' | | separator ' + 'characters. |\n' + ' ' + '+-----------+------------------------------------------------------------+\n' + ' | None | The same as ' + '"\'d\'". |\n' + ' ' + '+-----------+------------------------------------------------------------+\n' + '\n' + 'In addition to the above presentation types, integers can ' + 'be formatted\n' + 'with the floating-point presentation types listed below ' + '(except "\'n\'"\n' + 'and "None"). When doing so, "float()" is used to convert ' + 'the integer\n' + 'to a floating-point number before formatting.\n' + '\n' + 'The available presentation types for "float" and "Decimal" ' + 'values are:\n' + '\n' + ' ' + '+-----------+------------------------------------------------------------+\n' + ' | Type | ' + 'Meaning ' + '|\n' + ' ' + '|===========|============================================================|\n' + ' | "\'e\'" | Scientific notation. For a given ' + 'precision "p", formats |\n' + ' | | the number in scientific notation with the ' + 'letter ‘e’ |\n' + ' | | separating the coefficient from the ' + 'exponent. The |\n' + ' | | coefficient has one digit before and "p" ' + 'digits after the |\n' + ' | | decimal point, for a total of "p + 1" ' + 'significant digits. |\n' + ' | | With no precision given, uses a precision ' + 'of "6" digits |\n' + ' | | after the decimal point for "float", and ' + 'shows all |\n' + ' | | coefficient digits for "Decimal". If ' + '"p=0", the decimal |\n' + ' | | point is omitted unless the "#" option is ' + 'used. |\n' + ' ' + '+-----------+------------------------------------------------------------+\n' + ' | "\'E\'" | Scientific notation. Same as "\'e\'" ' + 'except it uses an upper |\n' + ' | | case ‘E’ as the separator ' + 'character. |\n' + ' ' + '+-----------+------------------------------------------------------------+\n' + ' | "\'f\'" | Fixed-point notation. For a given ' + 'precision "p", formats |\n' + ' | | the number as a decimal number with ' + 'exactly "p" digits |\n' + ' | | following the decimal point. With no ' + 'precision given, uses |\n' + ' | | a precision of "6" digits after the ' + 'decimal point for |\n' + ' | | "float", and uses a precision large enough ' + 'to show all |\n' + ' | | coefficient digits for "Decimal". If ' + '"p=0", the decimal |\n' + ' | | point is omitted unless the "#" option is ' + 'used. |\n' + ' ' + '+-----------+------------------------------------------------------------+\n' + ' | "\'F\'" | Fixed-point notation. Same as "\'f\'", ' + 'but converts "nan" to |\n' + ' | | "NAN" and "inf" to ' + '"INF". |\n' + ' ' + '+-----------+------------------------------------------------------------+\n' + ' | "\'g\'" | General format. For a given precision ' + '"p >= 1", this |\n' + ' | | rounds the number to "p" significant ' + 'digits and then |\n' + ' | | formats the result in either fixed-point ' + 'format or in |\n' + ' | | scientific notation, depending on its ' + 'magnitude. A |\n' + ' | | precision of "0" is treated as equivalent ' + 'to a precision |\n' + ' | | of "1". The precise rules are as follows: ' + 'suppose that |\n' + ' | | the result formatted with presentation ' + 'type "\'e\'" and |\n' + ' | | precision "p-1" would have exponent ' + '"exp". Then, if "m <= |\n' + ' | | exp < p", where "m" is -4 for floats and ' + '-6 for |\n' + ' | | "Decimals", the number is formatted with ' + 'presentation type |\n' + ' | | "\'f\'" and precision "p-1-exp". ' + 'Otherwise, the number is |\n' + ' | | formatted with presentation type "\'e\'" ' + 'and precision |\n' + ' | | "p-1". In both cases insignificant ' + 'trailing zeros are |\n' + ' | | removed from the significand, and the ' + 'decimal point is |\n' + ' | | also removed if there are no remaining ' + 'digits following |\n' + ' | | it, unless the "\'#\'" option is used. ' + 'With no precision |\n' + ' | | given, uses a precision of "6" significant ' + 'digits for |\n' + ' | | "float". For "Decimal", the coefficient of ' + 'the result is |\n' + ' | | formed from the coefficient digits of the ' + 'value; |\n' + ' | | scientific notation is used for values ' + 'smaller than "1e-6" |\n' + ' | | in absolute value and values where the ' + 'place value of the |\n' + ' | | least significant digit is larger than 1, ' + 'and fixed-point |\n' + ' | | notation is used otherwise. Positive and ' + 'negative |\n' + ' | | infinity, positive and negative zero, and ' + 'nans, are |\n' + ' | | formatted as "inf", "-inf", "0", "-0" and ' + '"nan" |\n' + ' | | respectively, regardless of the ' + 'precision. |\n' + ' ' + '+-----------+------------------------------------------------------------+\n' + ' | "\'G\'" | General format. Same as "\'g\'" except ' + 'switches to "\'E\'" if |\n' + ' | | the number gets too large. The ' + 'representations of infinity |\n' + ' | | and NaN are uppercased, ' + 'too. |\n' + ' ' + '+-----------+------------------------------------------------------------+\n' + ' | "\'n\'" | Number. This is the same as "\'g\'", ' + 'except that it uses the |\n' + ' | | current locale setting to insert the ' + 'appropriate number |\n' + ' | | separator ' + 'characters. |\n' + ' ' + '+-----------+------------------------------------------------------------+\n' + ' | "\'%\'" | Percentage. Multiplies the number by 100 ' + 'and displays in |\n' + ' | | fixed ("\'f\'") format, followed by a ' + 'percent sign. |\n' + ' ' + '+-----------+------------------------------------------------------------+\n' + ' | None | For "float" this is like the "\'g\'" type, ' + 'except that when |\n' + ' | | fixed- point notation is used to format ' + 'the result, it |\n' + ' | | always includes at least one digit past ' + 'the decimal point, |\n' + ' | | and switches to the scientific notation ' + 'when "exp >= p - |\n' + ' | | 1". When the precision is not specified, ' + 'the latter will |\n' + ' | | be as large as needed to represent the ' + 'given value |\n' + ' | | faithfully. For "Decimal", this is the ' + 'same as either |\n' + ' | | "\'g\'" or "\'G\'" depending on the value ' + 'of |\n' + ' | | "context.capitals" for the current decimal ' + 'context. The |\n' + ' | | overall effect is to match the output of ' + '"str()" as |\n' + ' | | altered by the other format ' + 'modifiers. |\n' + ' ' + '+-----------+------------------------------------------------------------+\n' + '\n' + 'The result should be correctly rounded to a given precision ' + '"p" of\n' + 'digits after the decimal point. The rounding mode for ' + '"float" matches\n' + 'that of the "round()" builtin. For "Decimal", the rounding ' + 'mode of\n' + 'the current context will be used.\n' + '\n' + 'The available presentation types for "complex" are the same ' + 'as those\n' + 'for "float" ("\'%\'" is not allowed). Both the real and ' + 'imaginary\n' + 'components of a complex number are formatted as ' + 'floating-point\n' + 'numbers, according to the specified presentation type. ' + 'They are\n' + 'separated by the mandatory sign of the imaginary part, the ' + 'latter\n' + 'being terminated by a "j" suffix. If the presentation type ' + 'is\n' + 'missing, the result will match the output of "str()" ' + '(complex numbers\n' + 'with a non-zero real part are also surrounded by ' + 'parentheses),\n' + 'possibly altered by other format modifiers.\n' + '\n' + '\n' + 'Format examples\n' + '===============\n' + '\n' + 'This section contains examples of the "str.format()" syntax ' + 'and\n' + 'comparison with the old "%"-formatting.\n' + '\n' + 'In most of the cases the syntax is similar to the old ' + '"%"-formatting,\n' + 'with the addition of the "{}" and with ":" used instead of ' + '"%". For\n' + 'example, "\'%03.2f\'" can be translated to "\'{:03.2f}\'".\n' + '\n' + 'The new format syntax also supports new and different ' + 'options, shown\n' + 'in the following examples.\n' + '\n' + 'Accessing arguments by position:\n' + '\n' + " >>> '{0}, {1}, {2}'.format('a', 'b', 'c')\n" + " 'a, b, c'\n" + " >>> '{}, {}, {}'.format('a', 'b', 'c') # 3.1+ only\n" + " 'a, b, c'\n" + " >>> '{2}, {1}, {0}'.format('a', 'b', 'c')\n" + " 'c, b, a'\n" + " >>> '{2}, {1}, {0}'.format(*'abc') # unpacking " + 'argument sequence\n' + " 'c, b, a'\n" + " >>> '{0}{1}{0}'.format('abra', 'cad') # arguments' " + 'indices can be repeated\n' + " 'abracadabra'\n" + '\n' + 'Accessing arguments by name:\n' + '\n' + " >>> 'Coordinates: {latitude}, " + "{longitude}'.format(latitude='37.24N', " + "longitude='-115.81W')\n" + " 'Coordinates: 37.24N, -115.81W'\n" + " >>> coord = {'latitude': '37.24N', 'longitude': " + "'-115.81W'}\n" + " >>> 'Coordinates: {latitude}, " + "{longitude}'.format(**coord)\n" + " 'Coordinates: 37.24N, -115.81W'\n" + '\n' + 'Accessing arguments’ attributes:\n' + '\n' + ' >>> c = 3-5j\n' + " >>> ('The complex number {0} is formed from the real " + "part {0.real} '\n" + " ... 'and the imaginary part {0.imag}.').format(c)\n" + " 'The complex number (3-5j) is formed from the real part " + "3.0 and the imaginary part -5.0.'\n" + ' >>> class Point:\n' + ' ... def __init__(self, x, y):\n' + ' ... self.x, self.y = x, y\n' + ' ... def __str__(self):\n' + " ... return 'Point({self.x}, " + "{self.y})'.format(self=self)\n" + ' ...\n' + ' >>> str(Point(4, 2))\n' + " 'Point(4, 2)'\n" + '\n' + 'Accessing arguments’ items:\n' + '\n' + ' >>> coord = (3, 5)\n' + " >>> 'X: {0[0]}; Y: {0[1]}'.format(coord)\n" + " 'X: 3; Y: 5'\n" + '\n' + 'Replacing "%s" and "%r":\n' + '\n' + ' >>> "repr() shows quotes: {!r}; str() doesn\'t: ' + '{!s}".format(\'test1\', \'test2\')\n' + ' "repr() shows quotes: \'test1\'; str() doesn\'t: test2"\n' + '\n' + 'Aligning the text and specifying a width:\n' + '\n' + " >>> '{:<30}'.format('left aligned')\n" + " 'left aligned '\n" + " >>> '{:>30}'.format('right aligned')\n" + " ' right aligned'\n" + " >>> '{:^30}'.format('centered')\n" + " ' centered '\n" + " >>> '{:*^30}'.format('centered') # use '*' as a fill " + 'char\n' + " '***********centered***********'\n" + '\n' + 'Replacing "%+f", "%-f", and "% f" and specifying a sign:\n' + '\n' + " >>> '{:+f}; {:+f}'.format(3.14, -3.14) # show it " + 'always\n' + " '+3.140000; -3.140000'\n" + " >>> '{: f}; {: f}'.format(3.14, -3.14) # show a space " + 'for positive numbers\n' + " ' 3.140000; -3.140000'\n" + " >>> '{:-f}; {:-f}'.format(3.14, -3.14) # show only the " + "minus -- same as '{:f}; {:f}'\n" + " '3.140000; -3.140000'\n" + '\n' + 'Replacing "%x" and "%o" and converting the value to ' + 'different bases:\n' + '\n' + ' >>> # format also supports binary numbers\n' + ' >>> "int: {0:d}; hex: {0:x}; oct: {0:o}; bin: ' + '{0:b}".format(42)\n' + " 'int: 42; hex: 2a; oct: 52; bin: 101010'\n" + ' >>> # with 0x, 0o, or 0b as prefix:\n' + ' >>> "int: {0:d}; hex: {0:#x}; oct: {0:#o}; bin: ' + '{0:#b}".format(42)\n' + " 'int: 42; hex: 0x2a; oct: 0o52; bin: 0b101010'\n" + '\n' + 'Using the comma as a thousands separator:\n' + '\n' + " >>> '{:,}'.format(1234567890)\n" + " '1,234,567,890'\n" + '\n' + 'Expressing a percentage:\n' + '\n' + ' >>> points = 19\n' + ' >>> total = 22\n' + " >>> 'Correct answers: {:.2%}'.format(points/total)\n" + " 'Correct answers: 86.36%'\n" + '\n' + 'Using type-specific formatting:\n' + '\n' + ' >>> import datetime\n' + ' >>> d = datetime.datetime(2010, 7, 4, 12, 15, 58)\n' + " >>> '{:%Y-%m-%d %H:%M:%S}'.format(d)\n" + " '2010-07-04 12:15:58'\n" + '\n' + 'Nesting arguments and more complex examples:\n' + '\n' + " >>> for align, text in zip('<^>', ['left', 'center', " + "'right']):\n" + " ... '{0:{fill}{align}16}'.format(text, fill=align, " + 'align=align)\n' + ' ...\n' + " 'left<<<<<<<<<<<<'\n" + " '^^^^^center^^^^^'\n" + " '>>>>>>>>>>>right'\n" + ' >>>\n' + ' >>> octets = [192, 168, 0, 1]\n' + " >>> '{:02X}{:02X}{:02X}{:02X}'.format(*octets)\n" + " 'C0A80001'\n" + ' >>> int(_, 16)\n' + ' 3232235521\n' + ' >>>\n' + ' >>> width = 5\n' + ' >>> for num in range(5,12): \n' + " ... for base in 'dXob':\n" + " ... print('{0:{width}{base}}'.format(num, " + "base=base, width=width), end=' ')\n" + ' ... print()\n' + ' ...\n' + ' 5 5 5 101\n' + ' 6 6 6 110\n' + ' 7 7 7 111\n' + ' 8 8 10 1000\n' + ' 9 9 11 1001\n' + ' 10 A 12 1010\n' + ' 11 B 13 1011\n', + 'function': 'Function definitions\n' + '********************\n' + '\n' + 'A function definition defines a user-defined function object ' + '(see\n' + 'section The standard type hierarchy):\n' + '\n' + ' funcdef ::= [decorators] "def" funcname ' + '[type_params] "(" [parameter_list] ")"\n' + ' ["->" expression] ":" suite\n' + ' decorators ::= decorator+\n' + ' decorator ::= "@" assignment_expression ' + 'NEWLINE\n' + ' parameter_list ::= defparameter ("," ' + 'defparameter)* "," "/" ["," [parameter_list_no_posonly]]\n' + ' | parameter_list_no_posonly\n' + ' parameter_list_no_posonly ::= defparameter ("," ' + 'defparameter)* ["," [parameter_list_starargs]]\n' + ' | parameter_list_starargs\n' + ' parameter_list_starargs ::= "*" [star_parameter] ("," ' + 'defparameter)* ["," ["**" parameter [","]]]\n' + ' | "**" parameter [","]\n' + ' parameter ::= identifier [":" expression]\n' + ' star_parameter ::= identifier [":" ["*"] ' + 'expression]\n' + ' defparameter ::= parameter ["=" expression]\n' + ' funcname ::= identifier\n' + '\n' + 'A function definition is an executable statement. Its execution ' + 'binds\n' + 'the function name in the current local namespace to a function ' + 'object\n' + '(a wrapper around the executable code for the function). This\n' + 'function object contains a reference to the current global ' + 'namespace\n' + 'as the global namespace to be used when the function is called.\n' + '\n' + 'The function definition does not execute the function body; this ' + 'gets\n' + 'executed only when the function is called. [4]\n' + '\n' + 'A function definition may be wrapped by one or more *decorator*\n' + 'expressions. Decorator expressions are evaluated when the ' + 'function is\n' + 'defined, in the scope that contains the function definition. ' + 'The\n' + 'result must be a callable, which is invoked with the function ' + 'object\n' + 'as the only argument. The returned value is bound to the ' + 'function name\n' + 'instead of the function object. Multiple decorators are applied ' + 'in\n' + 'nested fashion. For example, the following code\n' + '\n' + ' @f1(arg)\n' + ' @f2\n' + ' def func(): pass\n' + '\n' + 'is roughly equivalent to\n' + '\n' + ' def func(): pass\n' + ' func = f1(arg)(f2(func))\n' + '\n' + 'except that the original function is not temporarily bound to ' + 'the name\n' + '"func".\n' + '\n' + 'Changed in version 3.9: Functions may be decorated with any ' + 'valid\n' + '"assignment_expression". Previously, the grammar was much more\n' + 'restrictive; see **PEP 614** for details.\n' + '\n' + 'A list of type parameters may be given in square brackets ' + 'between the\n' + 'function’s name and the opening parenthesis for its parameter ' + 'list.\n' + 'This indicates to static type checkers that the function is ' + 'generic.\n' + 'At runtime, the type parameters can be retrieved from the ' + 'function’s\n' + '"__type_params__" attribute. See Generic functions for more.\n' + '\n' + 'Changed in version 3.12: Type parameter lists are new in Python ' + '3.12.\n' + '\n' + 'When one or more *parameters* have the form *parameter* "="\n' + '*expression*, the function is said to have “default parameter ' + 'values.”\n' + 'For a parameter with a default value, the corresponding ' + '*argument* may\n' + 'be omitted from a call, in which case the parameter’s default ' + 'value is\n' + 'substituted. If a parameter has a default value, all following\n' + 'parameters up until the “"*"” must also have a default value — ' + 'this is\n' + 'a syntactic restriction that is not expressed by the grammar.\n' + '\n' + '**Default parameter values are evaluated from left to right when ' + 'the\n' + 'function definition is executed.** This means that the ' + 'expression is\n' + 'evaluated once, when the function is defined, and that the same ' + '“pre-\n' + 'computed” value is used for each call. This is especially ' + 'important\n' + 'to understand when a default parameter value is a mutable ' + 'object, such\n' + 'as a list or a dictionary: if the function modifies the object ' + '(e.g.\n' + 'by appending an item to a list), the default parameter value is ' + 'in\n' + 'effect modified. This is generally not what was intended. A ' + 'way\n' + 'around this is to use "None" as the default, and explicitly test ' + 'for\n' + 'it in the body of the function, e.g.:\n' + '\n' + ' def whats_on_the_telly(penguin=None):\n' + ' if penguin is None:\n' + ' penguin = []\n' + ' penguin.append("property of the zoo")\n' + ' return penguin\n' + '\n' + 'Function call semantics are described in more detail in section ' + 'Calls.\n' + 'A function call always assigns values to all parameters ' + 'mentioned in\n' + 'the parameter list, either from positional arguments, from ' + 'keyword\n' + 'arguments, or from default values. If the form “"*identifier"” ' + 'is\n' + 'present, it is initialized to a tuple receiving any excess ' + 'positional\n' + 'parameters, defaulting to the empty tuple. If the form\n' + '“"**identifier"” is present, it is initialized to a new ordered\n' + 'mapping receiving any excess keyword arguments, defaulting to a ' + 'new\n' + 'empty mapping of the same type. Parameters after “"*"” or\n' + '“"*identifier"” are keyword-only parameters and may only be ' + 'passed by\n' + 'keyword arguments. Parameters before “"/"” are positional-only\n' + 'parameters and may only be passed by positional arguments.\n' + '\n' + 'Changed in version 3.8: The "/" function parameter syntax may be ' + 'used\n' + 'to indicate positional-only parameters. See **PEP 570** for ' + 'details.\n' + '\n' + 'Parameters may have an *annotation* of the form “": ' + 'expression"”\n' + 'following the parameter name. Any parameter may have an ' + 'annotation,\n' + 'even those of the form "*identifier" or "**identifier". (As a ' + 'special\n' + 'case, parameters of the form "*identifier" may have an ' + 'annotation “":\n' + '*expression"”.) Functions may have “return” annotation of the ' + 'form\n' + '“"-> expression"” after the parameter list. These annotations ' + 'can be\n' + 'any valid Python expression. The presence of annotations does ' + 'not\n' + 'change the semantics of a function. The annotation values are\n' + 'available as values of a dictionary keyed by the parameters’ ' + 'names in\n' + 'the "__annotations__" attribute of the function object. If the\n' + '"annotations" import from "__future__" is used, annotations are\n' + 'preserved as strings at runtime which enables postponed ' + 'evaluation.\n' + 'Otherwise, they are evaluated when the function definition is\n' + 'executed. In this case annotations may be evaluated in a ' + 'different\n' + 'order than they appear in the source code.\n' + '\n' + 'Changed in version 3.11: Parameters of the form “"*identifier"” ' + 'may\n' + 'have an annotation “": *expression"”. See **PEP 646**.\n' + '\n' + 'It is also possible to create anonymous functions (functions not ' + 'bound\n' + 'to a name), for immediate use in expressions. This uses lambda\n' + 'expressions, described in section Lambdas. Note that the ' + 'lambda\n' + 'expression is merely a shorthand for a simplified function ' + 'definition;\n' + 'a function defined in a “"def"” statement can be passed around ' + 'or\n' + 'assigned to another name just like a function defined by a ' + 'lambda\n' + 'expression. The “"def"” form is actually more powerful since ' + 'it\n' + 'allows the execution of multiple statements and annotations.\n' + '\n' + '**Programmer’s note:** Functions are first-class objects. A ' + '“"def"”\n' + 'statement executed inside a function definition defines a local\n' + 'function that can be returned or passed around. Free variables ' + 'used\n' + 'in the nested function can access the local variables of the ' + 'function\n' + 'containing the def. See section Naming and binding for ' + 'details.\n' + '\n' + 'See also:\n' + '\n' + ' **PEP 3107** - Function Annotations\n' + ' The original specification for function annotations.\n' + '\n' + ' **PEP 484** - Type Hints\n' + ' Definition of a standard meaning for annotations: type ' + 'hints.\n' + '\n' + ' **PEP 526** - Syntax for Variable Annotations\n' + ' Ability to type hint variable declarations, including ' + 'class\n' + ' variables and instance variables.\n' + '\n' + ' **PEP 563** - Postponed Evaluation of Annotations\n' + ' Support for forward references within annotations by ' + 'preserving\n' + ' annotations in a string form at runtime instead of eager\n' + ' evaluation.\n' + '\n' + ' **PEP 318** - Decorators for Functions and Methods\n' + ' Function and method decorators were introduced. Class ' + 'decorators\n' + ' were introduced in **PEP 3129**.\n', + 'global': 'The "global" statement\n' + '**********************\n' + '\n' + ' global_stmt ::= "global" identifier ("," identifier)*\n' + '\n' + 'The "global" statement causes the listed identifiers to be ' + 'interpreted\n' + 'as globals. It would be impossible to assign to a global variable\n' + 'without "global", although free variables may refer to globals ' + 'without\n' + 'being declared global.\n' + '\n' + 'The "global" statement applies to the entire scope of a function ' + 'or\n' + 'class body. A "SyntaxError" is raised if a variable is used or\n' + 'assigned to prior to its global declaration in the scope.\n' + '\n' + '**Programmer’s note:** "global" is a directive to the parser. It\n' + 'applies only to code parsed at the same time as the "global"\n' + 'statement. In particular, a "global" statement contained in a ' + 'string\n' + 'or code object supplied to the built-in "exec()" function does ' + 'not\n' + 'affect the code block *containing* the function call, and code\n' + 'contained in such a string is unaffected by "global" statements in ' + 'the\n' + 'code containing the function call. The same applies to the ' + '"eval()"\n' + 'and "compile()" functions.\n', + 'id-classes': 'Reserved classes of identifiers\n' + '*******************************\n' + '\n' + 'Certain classes of identifiers (besides keywords) have ' + 'special\n' + 'meanings. These classes are identified by the patterns of ' + 'leading and\n' + 'trailing underscore characters:\n' + '\n' + '"_*"\n' + ' Not imported by "from module import *".\n' + '\n' + '"_"\n' + ' In a "case" pattern within a "match" statement, "_" is a ' + 'soft\n' + ' keyword that denotes a wildcard.\n' + '\n' + ' Separately, the interactive interpreter makes the result of ' + 'the\n' + ' last evaluation available in the variable "_". (It is ' + 'stored in the\n' + ' "builtins" module, alongside built-in functions like ' + '"print".)\n' + '\n' + ' Elsewhere, "_" is a regular identifier. It is often used to ' + 'name\n' + ' “special” items, but it is not special to Python itself.\n' + '\n' + ' Note:\n' + '\n' + ' The name "_" is often used in conjunction with\n' + ' internationalization; refer to the documentation for the\n' + ' "gettext" module for more information on this ' + 'convention.It is\n' + ' also commonly used for unused variables.\n' + '\n' + '"__*__"\n' + ' System-defined names, informally known as “dunder” names. ' + 'These\n' + ' names are defined by the interpreter and its ' + 'implementation\n' + ' (including the standard library). Current system names are\n' + ' discussed in the Special method names section and ' + 'elsewhere. More\n' + ' will likely be defined in future versions of Python. *Any* ' + 'use of\n' + ' "__*__" names, in any context, that does not follow ' + 'explicitly\n' + ' documented use, is subject to breakage without warning.\n' + '\n' + '"__*"\n' + ' Class-private names. Names in this category, when used ' + 'within the\n' + ' context of a class definition, are re-written to use a ' + 'mangled form\n' + ' to help avoid name clashes between “private” attributes of ' + 'base and\n' + ' derived classes. See section Identifiers (Names).\n', + 'identifiers': 'Identifiers and keywords\n' + '************************\n' + '\n' + 'Identifiers (also referred to as *names*) are described by ' + 'the\n' + 'following lexical definitions.\n' + '\n' + 'The syntax of identifiers in Python is based on the Unicode ' + 'standard\n' + 'annex UAX-31, with elaboration and changes as defined below; ' + 'see also\n' + '**PEP 3131** for further details.\n' + '\n' + 'Within the ASCII range (U+0001..U+007F), the valid characters ' + 'for\n' + 'identifiers include the uppercase and lowercase letters "A" ' + 'through\n' + '"Z", the underscore "_" and, except for the first character, ' + 'the\n' + 'digits "0" through "9". Python 3.0 introduced additional ' + 'characters\n' + 'from outside the ASCII range (see **PEP 3131**). For these\n' + 'characters, the classification uses the version of the ' + 'Unicode\n' + 'Character Database as included in the "unicodedata" module.\n' + '\n' + 'Identifiers are unlimited in length. Case is significant.\n' + '\n' + ' identifier ::= xid_start xid_continue*\n' + ' id_start ::= \n' + ' id_continue ::= \n' + ' xid_start ::= \n' + ' xid_continue ::= \n' + '\n' + 'The Unicode category codes mentioned above stand for:\n' + '\n' + '* *Lu* - uppercase letters\n' + '\n' + '* *Ll* - lowercase letters\n' + '\n' + '* *Lt* - titlecase letters\n' + '\n' + '* *Lm* - modifier letters\n' + '\n' + '* *Lo* - other letters\n' + '\n' + '* *Nl* - letter numbers\n' + '\n' + '* *Mn* - nonspacing marks\n' + '\n' + '* *Mc* - spacing combining marks\n' + '\n' + '* *Nd* - decimal numbers\n' + '\n' + '* *Pc* - connector punctuations\n' + '\n' + '* *Other_ID_Start* - explicit list of characters in ' + 'PropList.txt to\n' + ' support backwards compatibility\n' + '\n' + '* *Other_ID_Continue* - likewise\n' + '\n' + 'All identifiers are converted into the normal form NFKC while ' + 'parsing;\n' + 'comparison of identifiers is based on NFKC.\n' + '\n' + 'A non-normative HTML file listing all valid identifier ' + 'characters for\n' + 'Unicode 15.0.0 can be found at\n' + 'https://www.unicode.org/Public/15.0.0/ucd/DerivedCoreProperties.txt\n' + '\n' + '\n' + 'Keywords\n' + '========\n' + '\n' + 'The following identifiers are used as reserved words, or ' + '*keywords* of\n' + 'the language, and cannot be used as ordinary identifiers. ' + 'They must\n' + 'be spelled exactly as written here:\n' + '\n' + ' False await else import pass\n' + ' None break except in raise\n' + ' True class finally is return\n' + ' and continue for lambda try\n' + ' as def from nonlocal while\n' + ' assert del global not with\n' + ' async elif if or yield\n' + '\n' + '\n' + 'Soft Keywords\n' + '=============\n' + '\n' + 'Added in version 3.10.\n' + '\n' + 'Some identifiers are only reserved under specific contexts. ' + 'These are\n' + 'known as *soft keywords*. The identifiers "match", "case", ' + '"type" and\n' + '"_" can syntactically act as keywords in certain contexts, ' + 'but this\n' + 'distinction is done at the parser level, not when ' + 'tokenizing.\n' + '\n' + 'As soft keywords, their use in the grammar is possible while ' + 'still\n' + 'preserving compatibility with existing code that uses these ' + 'names as\n' + 'identifier names.\n' + '\n' + '"match", "case", and "_" are used in the "match" statement. ' + '"type" is\n' + 'used in the "type" statement.\n' + '\n' + 'Changed in version 3.12: "type" is now a soft keyword.\n' + '\n' + '\n' + 'Reserved classes of identifiers\n' + '===============================\n' + '\n' + 'Certain classes of identifiers (besides keywords) have ' + 'special\n' + 'meanings. These classes are identified by the patterns of ' + 'leading and\n' + 'trailing underscore characters:\n' + '\n' + '"_*"\n' + ' Not imported by "from module import *".\n' + '\n' + '"_"\n' + ' In a "case" pattern within a "match" statement, "_" is a ' + 'soft\n' + ' keyword that denotes a wildcard.\n' + '\n' + ' Separately, the interactive interpreter makes the result ' + 'of the\n' + ' last evaluation available in the variable "_". (It is ' + 'stored in the\n' + ' "builtins" module, alongside built-in functions like ' + '"print".)\n' + '\n' + ' Elsewhere, "_" is a regular identifier. It is often used ' + 'to name\n' + ' “special” items, but it is not special to Python itself.\n' + '\n' + ' Note:\n' + '\n' + ' The name "_" is often used in conjunction with\n' + ' internationalization; refer to the documentation for ' + 'the\n' + ' "gettext" module for more information on this ' + 'convention.It is\n' + ' also commonly used for unused variables.\n' + '\n' + '"__*__"\n' + ' System-defined names, informally known as “dunder” names. ' + 'These\n' + ' names are defined by the interpreter and its ' + 'implementation\n' + ' (including the standard library). Current system names ' + 'are\n' + ' discussed in the Special method names section and ' + 'elsewhere. More\n' + ' will likely be defined in future versions of Python. ' + '*Any* use of\n' + ' "__*__" names, in any context, that does not follow ' + 'explicitly\n' + ' documented use, is subject to breakage without warning.\n' + '\n' + '"__*"\n' + ' Class-private names. Names in this category, when used ' + 'within the\n' + ' context of a class definition, are re-written to use a ' + 'mangled form\n' + ' to help avoid name clashes between “private” attributes of ' + 'base and\n' + ' derived classes. See section Identifiers (Names).\n', + 'if': 'The "if" statement\n' + '******************\n' + '\n' + 'The "if" statement is used for conditional execution:\n' + '\n' + ' if_stmt ::= "if" assignment_expression ":" suite\n' + ' ("elif" assignment_expression ":" suite)*\n' + ' ["else" ":" suite]\n' + '\n' + 'It selects exactly one of the suites by evaluating the expressions ' + 'one\n' + 'by one until one is found to be true (see section Boolean operations\n' + 'for the definition of true and false); then that suite is executed\n' + '(and no other part of the "if" statement is executed or evaluated).\n' + 'If all expressions are false, the suite of the "else" clause, if\n' + 'present, is executed.\n', + 'imaginary': 'Imaginary literals\n' + '******************\n' + '\n' + 'Imaginary literals are described by the following lexical ' + 'definitions:\n' + '\n' + ' imagnumber ::= (floatnumber | digitpart) ("j" | "J")\n' + '\n' + 'An imaginary literal yields a complex number with a real part ' + 'of 0.0.\n' + 'Complex numbers are represented as a pair of floating-point ' + 'numbers\n' + 'and have the same restrictions on their range. To create a ' + 'complex\n' + 'number with a nonzero real part, add a floating-point number to ' + 'it,\n' + 'e.g., "(3+4j)". Some examples of imaginary literals:\n' + '\n' + ' 3.14j 10.j 10j .001j 1e100j 3.14e-10j ' + '3.14_15_93j\n', + 'import': 'The "import" statement\n' + '**********************\n' + '\n' + ' import_stmt ::= "import" module ["as" identifier] ("," ' + 'module ["as" identifier])*\n' + ' | "from" relative_module "import" identifier ' + '["as" identifier]\n' + ' ("," identifier ["as" identifier])*\n' + ' | "from" relative_module "import" "(" ' + 'identifier ["as" identifier]\n' + ' ("," identifier ["as" identifier])* [","] ")"\n' + ' | "from" relative_module "import" "*"\n' + ' module ::= (identifier ".")* identifier\n' + ' relative_module ::= "."* module | "."+\n' + '\n' + 'The basic import statement (no "from" clause) is executed in two\n' + 'steps:\n' + '\n' + '1. find a module, loading and initializing it if necessary\n' + '\n' + '2. define a name or names in the local namespace for the scope ' + 'where\n' + ' the "import" statement occurs.\n' + '\n' + 'When the statement contains multiple clauses (separated by commas) ' + 'the\n' + 'two steps are carried out separately for each clause, just as ' + 'though\n' + 'the clauses had been separated out into individual import ' + 'statements.\n' + '\n' + 'The details of the first step, finding and loading modules, are\n' + 'described in greater detail in the section on the import system, ' + 'which\n' + 'also describes the various types of packages and modules that can ' + 'be\n' + 'imported, as well as all the hooks that can be used to customize ' + 'the\n' + 'import system. Note that failures in this step may indicate ' + 'either\n' + 'that the module could not be located, *or* that an error occurred\n' + 'while initializing the module, which includes execution of the\n' + 'module’s code.\n' + '\n' + 'If the requested module is retrieved successfully, it will be ' + 'made\n' + 'available in the local namespace in one of three ways:\n' + '\n' + '* If the module name is followed by "as", then the name following ' + '"as"\n' + ' is bound directly to the imported module.\n' + '\n' + '* If no other name is specified, and the module being imported is ' + 'a\n' + ' top level module, the module’s name is bound in the local ' + 'namespace\n' + ' as a reference to the imported module\n' + '\n' + '* If the module being imported is *not* a top level module, then ' + 'the\n' + ' name of the top level package that contains the module is bound ' + 'in\n' + ' the local namespace as a reference to the top level package. ' + 'The\n' + ' imported module must be accessed using its full qualified name\n' + ' rather than directly\n' + '\n' + 'The "from" form uses a slightly more complex process:\n' + '\n' + '1. find the module specified in the "from" clause, loading and\n' + ' initializing it if necessary;\n' + '\n' + '2. for each of the identifiers specified in the "import" clauses:\n' + '\n' + ' 1. check if the imported module has an attribute by that name\n' + '\n' + ' 2. if not, attempt to import a submodule with that name and ' + 'then\n' + ' check the imported module again for that attribute\n' + '\n' + ' 3. if the attribute is not found, "ImportError" is raised.\n' + '\n' + ' 4. otherwise, a reference to that value is stored in the local\n' + ' namespace, using the name in the "as" clause if it is ' + 'present,\n' + ' otherwise using the attribute name\n' + '\n' + 'Examples:\n' + '\n' + ' import foo # foo imported and bound locally\n' + ' import foo.bar.baz # foo, foo.bar, and foo.bar.baz ' + 'imported, foo bound locally\n' + ' import foo.bar.baz as fbb # foo, foo.bar, and foo.bar.baz ' + 'imported, foo.bar.baz bound as fbb\n' + ' from foo.bar import baz # foo, foo.bar, and foo.bar.baz ' + 'imported, foo.bar.baz bound as baz\n' + ' from foo import attr # foo imported and foo.attr bound as ' + 'attr\n' + '\n' + 'If the list of identifiers is replaced by a star ("\'*\'"), all ' + 'public\n' + 'names defined in the module are bound in the local namespace for ' + 'the\n' + 'scope where the "import" statement occurs.\n' + '\n' + 'The *public names* defined by a module are determined by checking ' + 'the\n' + 'module’s namespace for a variable named "__all__"; if defined, it ' + 'must\n' + 'be a sequence of strings which are names defined or imported by ' + 'that\n' + 'module. The names given in "__all__" are all considered public ' + 'and\n' + 'are required to exist. If "__all__" is not defined, the set of ' + 'public\n' + 'names includes all names found in the module’s namespace which do ' + 'not\n' + 'begin with an underscore character ("\'_\'"). "__all__" should ' + 'contain\n' + 'the entire public API. It is intended to avoid accidentally ' + 'exporting\n' + 'items that are not part of the API (such as library modules which ' + 'were\n' + 'imported and used within the module).\n' + '\n' + 'The wild card form of import — "from module import *" — is only\n' + 'allowed at the module level. Attempting to use it in class or\n' + 'function definitions will raise a "SyntaxError".\n' + '\n' + 'When specifying what module to import you do not have to specify ' + 'the\n' + 'absolute name of the module. When a module or package is ' + 'contained\n' + 'within another package it is possible to make a relative import ' + 'within\n' + 'the same top package without having to mention the package name. ' + 'By\n' + 'using leading dots in the specified module or package after "from" ' + 'you\n' + 'can specify how high to traverse up the current package hierarchy\n' + 'without specifying exact names. One leading dot means the current\n' + 'package where the module making the import exists. Two dots means ' + 'up\n' + 'one package level. Three dots is up two levels, etc. So if you ' + 'execute\n' + '"from . import mod" from a module in the "pkg" package then you ' + 'will\n' + 'end up importing "pkg.mod". If you execute "from ..subpkg2 import ' + 'mod"\n' + 'from within "pkg.subpkg1" you will import "pkg.subpkg2.mod". The\n' + 'specification for relative imports is contained in the Package\n' + 'Relative Imports section.\n' + '\n' + '"importlib.import_module()" is provided to support applications ' + 'that\n' + 'determine dynamically the modules to be loaded.\n' + '\n' + 'Raises an auditing event "import" with arguments "module", ' + '"filename",\n' + '"sys.path", "sys.meta_path", "sys.path_hooks".\n' + '\n' + '\n' + 'Future statements\n' + '=================\n' + '\n' + 'A *future statement* is a directive to the compiler that a ' + 'particular\n' + 'module should be compiled using syntax or semantics that will be\n' + 'available in a specified future release of Python where the ' + 'feature\n' + 'becomes standard.\n' + '\n' + 'The future statement is intended to ease migration to future ' + 'versions\n' + 'of Python that introduce incompatible changes to the language. ' + 'It\n' + 'allows use of the new features on a per-module basis before the\n' + 'release in which the feature becomes standard.\n' + '\n' + ' future_stmt ::= "from" "__future__" "import" feature ["as" ' + 'identifier]\n' + ' ("," feature ["as" identifier])*\n' + ' | "from" "__future__" "import" "(" feature ' + '["as" identifier]\n' + ' ("," feature ["as" identifier])* [","] ")"\n' + ' feature ::= identifier\n' + '\n' + 'A future statement must appear near the top of the module. The ' + 'only\n' + 'lines that can appear before a future statement are:\n' + '\n' + '* the module docstring (if any),\n' + '\n' + '* comments,\n' + '\n' + '* blank lines, and\n' + '\n' + '* other future statements.\n' + '\n' + 'The only feature that requires using the future statement is\n' + '"annotations" (see **PEP 563**).\n' + '\n' + 'All historical features enabled by the future statement are still\n' + 'recognized by Python 3. The list includes "absolute_import",\n' + '"division", "generators", "generator_stop", "unicode_literals",\n' + '"print_function", "nested_scopes" and "with_statement". They are ' + 'all\n' + 'redundant because they are always enabled, and only kept for ' + 'backwards\n' + 'compatibility.\n' + '\n' + 'A future statement is recognized and treated specially at compile\n' + 'time: Changes to the semantics of core constructs are often\n' + 'implemented by generating different code. It may even be the ' + 'case\n' + 'that a new feature introduces new incompatible syntax (such as a ' + 'new\n' + 'reserved word), in which case the compiler may need to parse the\n' + 'module differently. Such decisions cannot be pushed off until\n' + 'runtime.\n' + '\n' + 'For any given release, the compiler knows which feature names ' + 'have\n' + 'been defined, and raises a compile-time error if a future ' + 'statement\n' + 'contains a feature not known to it.\n' + '\n' + 'The direct runtime semantics are the same as for any import ' + 'statement:\n' + 'there is a standard module "__future__", described later, and it ' + 'will\n' + 'be imported in the usual way at the time the future statement is\n' + 'executed.\n' + '\n' + 'The interesting runtime semantics depend on the specific feature\n' + 'enabled by the future statement.\n' + '\n' + 'Note that there is nothing special about the statement:\n' + '\n' + ' import __future__ [as name]\n' + '\n' + 'That is not a future statement; it’s an ordinary import statement ' + 'with\n' + 'no special semantics or syntax restrictions.\n' + '\n' + 'Code compiled by calls to the built-in functions "exec()" and\n' + '"compile()" that occur in a module "M" containing a future ' + 'statement\n' + 'will, by default, use the new syntax or semantics associated with ' + 'the\n' + 'future statement. This can be controlled by optional arguments ' + 'to\n' + '"compile()" — see the documentation of that function for details.\n' + '\n' + 'A future statement typed at an interactive interpreter prompt ' + 'will\n' + 'take effect for the rest of the interpreter session. If an\n' + 'interpreter is started with the "-i" option, is passed a script ' + 'name\n' + 'to execute, and the script includes a future statement, it will be ' + 'in\n' + 'effect in the interactive session started after the script is\n' + 'executed.\n' + '\n' + 'See also:\n' + '\n' + ' **PEP 236** - Back to the __future__\n' + ' The original proposal for the __future__ mechanism.\n', + 'in': 'Membership test operations\n' + '**************************\n' + '\n' + 'The operators "in" and "not in" test for membership. "x in s"\n' + 'evaluates to "True" if *x* is a member of *s*, and "False" otherwise.\n' + '"x not in s" returns the negation of "x in s". All built-in ' + 'sequences\n' + 'and set types support this as well as dictionary, for which "in" ' + 'tests\n' + 'whether the dictionary has a given key. For container types such as\n' + 'list, tuple, set, frozenset, dict, or collections.deque, the\n' + 'expression "x in y" is equivalent to "any(x is e or x == e for e in\n' + 'y)".\n' + '\n' + 'For the string and bytes types, "x in y" is "True" if and only if *x*\n' + 'is a substring of *y*. An equivalent test is "y.find(x) != -1".\n' + 'Empty strings are always considered to be a substring of any other\n' + 'string, so """ in "abc"" will return "True".\n' + '\n' + 'For user-defined classes which define the "__contains__()" method, "x\n' + 'in y" returns "True" if "y.__contains__(x)" returns a true value, and\n' + '"False" otherwise.\n' + '\n' + 'For user-defined classes which do not define "__contains__()" but do\n' + 'define "__iter__()", "x in y" is "True" if some value "z", for which\n' + 'the expression "x is z or x == z" is true, is produced while ' + 'iterating\n' + 'over "y". If an exception is raised during the iteration, it is as if\n' + '"in" raised that exception.\n' + '\n' + 'Lastly, the old-style iteration protocol is tried: if a class defines\n' + '"__getitem__()", "x in y" is "True" if and only if there is a non-\n' + 'negative integer index *i* such that "x is y[i] or x == y[i]", and no\n' + 'lower integer index raises the "IndexError" exception. (If any other\n' + 'exception is raised, it is as if "in" raised that exception).\n' + '\n' + 'The operator "not in" is defined to have the inverse truth value of\n' + '"in".\n', + 'integers': 'Integer literals\n' + '****************\n' + '\n' + 'Integer literals are described by the following lexical ' + 'definitions:\n' + '\n' + ' integer ::= decinteger | bininteger | octinteger | ' + 'hexinteger\n' + ' decinteger ::= nonzerodigit (["_"] digit)* | "0"+ (["_"] ' + '"0")*\n' + ' bininteger ::= "0" ("b" | "B") (["_"] bindigit)+\n' + ' octinteger ::= "0" ("o" | "O") (["_"] octdigit)+\n' + ' hexinteger ::= "0" ("x" | "X") (["_"] hexdigit)+\n' + ' nonzerodigit ::= "1"..."9"\n' + ' digit ::= "0"..."9"\n' + ' bindigit ::= "0" | "1"\n' + ' octdigit ::= "0"..."7"\n' + ' hexdigit ::= digit | "a"..."f" | "A"..."F"\n' + '\n' + 'There is no limit for the length of integer literals apart from ' + 'what\n' + 'can be stored in available memory.\n' + '\n' + 'Underscores are ignored for determining the numeric value of ' + 'the\n' + 'literal. They can be used to group digits for enhanced ' + 'readability.\n' + 'One underscore can occur between digits, and after base ' + 'specifiers\n' + 'like "0x".\n' + '\n' + 'Note that leading zeros in a non-zero decimal number are not ' + 'allowed.\n' + 'This is for disambiguation with C-style octal literals, which ' + 'Python\n' + 'used before version 3.0.\n' + '\n' + 'Some examples of integer literals:\n' + '\n' + ' 7 2147483647 0o177 0b100110111\n' + ' 3 79228162514264337593543950336 0o377 0xdeadbeef\n' + ' 100_000_000_000 0b_1110_0101\n' + '\n' + 'Changed in version 3.6: Underscores are now allowed for ' + 'grouping\n' + 'purposes in literals.\n', + 'lambda': 'Lambdas\n' + '*******\n' + '\n' + ' lambda_expr ::= "lambda" [parameter_list] ":" expression\n' + '\n' + 'Lambda expressions (sometimes called lambda forms) are used to ' + 'create\n' + 'anonymous functions. The expression "lambda parameters: ' + 'expression"\n' + 'yields a function object. The unnamed object behaves like a ' + 'function\n' + 'object defined with:\n' + '\n' + ' def (parameters):\n' + ' return expression\n' + '\n' + 'See section Function definitions for the syntax of parameter ' + 'lists.\n' + 'Note that functions created with lambda expressions cannot ' + 'contain\n' + 'statements or annotations.\n', + 'lists': 'List displays\n' + '*************\n' + '\n' + 'A list display is a possibly empty series of expressions enclosed ' + 'in\n' + 'square brackets:\n' + '\n' + ' list_display ::= "[" [flexible_expression_list | comprehension] ' + '"]"\n' + '\n' + 'A list display yields a new list object, the contents being ' + 'specified\n' + 'by either a list of expressions or a comprehension. When a comma-\n' + 'separated list of expressions is supplied, its elements are ' + 'evaluated\n' + 'from left to right and placed into the list object in that order.\n' + 'When a comprehension is supplied, the list is constructed from the\n' + 'elements resulting from the comprehension.\n', + 'naming': 'Naming and binding\n' + '******************\n' + '\n' + '\n' + 'Binding of names\n' + '================\n' + '\n' + '*Names* refer to objects. Names are introduced by name binding\n' + 'operations.\n' + '\n' + 'The following constructs bind names:\n' + '\n' + '* formal parameters to functions,\n' + '\n' + '* class definitions,\n' + '\n' + '* function definitions,\n' + '\n' + '* assignment expressions,\n' + '\n' + '* targets that are identifiers if occurring in an assignment:\n' + '\n' + ' * "for" loop header,\n' + '\n' + ' * after "as" in a "with" statement, "except" clause, "except*"\n' + ' clause, or in the as-pattern in structural pattern matching,\n' + '\n' + ' * in a capture pattern in structural pattern matching\n' + '\n' + '* "import" statements.\n' + '\n' + '* "type" statements.\n' + '\n' + '* type parameter lists.\n' + '\n' + 'The "import" statement of the form "from ... import *" binds all ' + 'names\n' + 'defined in the imported module, except those beginning with an\n' + 'underscore. This form may only be used at the module level.\n' + '\n' + 'A target occurring in a "del" statement is also considered bound ' + 'for\n' + 'this purpose (though the actual semantics are to unbind the ' + 'name).\n' + '\n' + 'Each assignment or import statement occurs within a block defined ' + 'by a\n' + 'class or function definition or at the module level (the ' + 'top-level\n' + 'code block).\n' + '\n' + 'If a name is bound in a block, it is a local variable of that ' + 'block,\n' + 'unless declared as "nonlocal" or "global". If a name is bound at ' + 'the\n' + 'module level, it is a global variable. (The variables of the ' + 'module\n' + 'code block are local and global.) If a variable is used in a ' + 'code\n' + 'block but not defined there, it is a *free variable*.\n' + '\n' + 'Each occurrence of a name in the program text refers to the ' + '*binding*\n' + 'of that name established by the following name resolution rules.\n' + '\n' + '\n' + 'Resolution of names\n' + '===================\n' + '\n' + 'A *scope* defines the visibility of a name within a block. If a ' + 'local\n' + 'variable is defined in a block, its scope includes that block. If ' + 'the\n' + 'definition occurs in a function block, the scope extends to any ' + 'blocks\n' + 'contained within the defining one, unless a contained block ' + 'introduces\n' + 'a different binding for the name.\n' + '\n' + 'When a name is used in a code block, it is resolved using the ' + 'nearest\n' + 'enclosing scope. The set of all such scopes visible to a code ' + 'block\n' + 'is called the block’s *environment*.\n' + '\n' + 'When a name is not found at all, a "NameError" exception is ' + 'raised. If\n' + 'the current scope is a function scope, and the name refers to a ' + 'local\n' + 'variable that has not yet been bound to a value at the point where ' + 'the\n' + 'name is used, an "UnboundLocalError" exception is raised.\n' + '"UnboundLocalError" is a subclass of "NameError".\n' + '\n' + 'If a name binding operation occurs anywhere within a code block, ' + 'all\n' + 'uses of the name within the block are treated as references to ' + 'the\n' + 'current block. This can lead to errors when a name is used within ' + 'a\n' + 'block before it is bound. This rule is subtle. Python lacks\n' + 'declarations and allows name binding operations to occur anywhere\n' + 'within a code block. The local variables of a code block can be\n' + 'determined by scanning the entire text of the block for name ' + 'binding\n' + 'operations. See the FAQ entry on UnboundLocalError for examples.\n' + '\n' + 'If the "global" statement occurs within a block, all uses of the ' + 'names\n' + 'specified in the statement refer to the bindings of those names in ' + 'the\n' + 'top-level namespace. Names are resolved in the top-level ' + 'namespace by\n' + 'searching the global namespace, i.e. the namespace of the module\n' + 'containing the code block, and the builtins namespace, the ' + 'namespace\n' + 'of the module "builtins". The global namespace is searched ' + 'first. If\n' + 'the names are not found there, the builtins namespace is searched\n' + 'next. If the names are also not found in the builtins namespace, ' + 'new\n' + 'variables are created in the global namespace. The global ' + 'statement\n' + 'must precede all uses of the listed names.\n' + '\n' + 'The "global" statement has the same scope as a name binding ' + 'operation\n' + 'in the same block. If the nearest enclosing scope for a free ' + 'variable\n' + 'contains a global statement, the free variable is treated as a ' + 'global.\n' + '\n' + 'The "nonlocal" statement causes corresponding names to refer to\n' + 'previously bound variables in the nearest enclosing function ' + 'scope.\n' + '"SyntaxError" is raised at compile time if the given name does ' + 'not\n' + 'exist in any enclosing function scope. Type parameters cannot be\n' + 'rebound with the "nonlocal" statement.\n' + '\n' + 'The namespace for a module is automatically created the first time ' + 'a\n' + 'module is imported. The main module for a script is always ' + 'called\n' + '"__main__".\n' + '\n' + 'Class definition blocks and arguments to "exec()" and "eval()" ' + 'are\n' + 'special in the context of name resolution. A class definition is ' + 'an\n' + 'executable statement that may use and define names. These ' + 'references\n' + 'follow the normal rules for name resolution with an exception ' + 'that\n' + 'unbound local variables are looked up in the global namespace. ' + 'The\n' + 'namespace of the class definition becomes the attribute dictionary ' + 'of\n' + 'the class. The scope of names defined in a class block is limited ' + 'to\n' + 'the class block; it does not extend to the code blocks of ' + 'methods.\n' + 'This includes comprehensions and generator expressions, but it ' + 'does\n' + 'not include annotation scopes, which have access to their ' + 'enclosing\n' + 'class scopes. This means that the following will fail:\n' + '\n' + ' class A:\n' + ' a = 42\n' + ' b = list(a + i for i in range(10))\n' + '\n' + 'However, the following will succeed:\n' + '\n' + ' class A:\n' + ' type Alias = Nested\n' + ' class Nested: pass\n' + '\n' + " print(A.Alias.__value__) # \n" + '\n' + '\n' + 'Annotation scopes\n' + '=================\n' + '\n' + 'Type parameter lists and "type" statements introduce *annotation\n' + 'scopes*, which behave mostly like function scopes, but with some\n' + 'exceptions discussed below. *Annotations* currently do not use\n' + 'annotation scopes, but they are expected to use annotation scopes ' + 'in\n' + 'Python 3.13 when **PEP 649** is implemented.\n' + '\n' + 'Annotation scopes are used in the following contexts:\n' + '\n' + '* Type parameter lists for generic type aliases.\n' + '\n' + '* Type parameter lists for generic functions. A generic ' + 'function’s\n' + ' annotations are executed within the annotation scope, but its\n' + ' defaults and decorators are not.\n' + '\n' + '* Type parameter lists for generic classes. A generic class’s ' + 'base\n' + ' classes and keyword arguments are executed within the ' + 'annotation\n' + ' scope, but its decorators are not.\n' + '\n' + '* The bounds and constraints for type variables (lazily ' + 'evaluated).\n' + '\n' + '* The value of type aliases (lazily evaluated).\n' + '\n' + 'Annotation scopes differ from function scopes in the following ' + 'ways:\n' + '\n' + '* Annotation scopes have access to their enclosing class ' + 'namespace. If\n' + ' an annotation scope is immediately within a class scope, or ' + 'within\n' + ' another annotation scope that is immediately within a class ' + 'scope,\n' + ' the code in the annotation scope can use names defined in the ' + 'class\n' + ' scope as if it were executed directly within the class body. ' + 'This\n' + ' contrasts with regular functions defined within classes, which\n' + ' cannot access names defined in the class scope.\n' + '\n' + '* Expressions in annotation scopes cannot contain "yield", "yield\n' + ' from", "await", or ":=" expressions. (These expressions are ' + 'allowed\n' + ' in other scopes contained within the annotation scope.)\n' + '\n' + '* Names defined in annotation scopes cannot be rebound with ' + '"nonlocal"\n' + ' statements in inner scopes. This includes only type parameters, ' + 'as\n' + ' no other syntactic elements that can appear within annotation ' + 'scopes\n' + ' can introduce new names.\n' + '\n' + '* While annotation scopes have an internal name, that name is not\n' + ' reflected in the *qualified name* of objects defined within the\n' + ' scope. Instead, the "__qualname__" of such objects is as if the\n' + ' object were defined in the enclosing scope.\n' + '\n' + 'Added in version 3.12: Annotation scopes were introduced in ' + 'Python\n' + '3.12 as part of **PEP 695**.\n' + '\n' + '\n' + 'Lazy evaluation\n' + '===============\n' + '\n' + 'The values of type aliases created through the "type" statement ' + 'are\n' + '*lazily evaluated*. The same applies to the bounds and constraints ' + 'of\n' + 'type variables created through the type parameter syntax. This ' + 'means\n' + 'that they are not evaluated when the type alias or type variable ' + 'is\n' + 'created. Instead, they are only evaluated when doing so is ' + 'necessary\n' + 'to resolve an attribute access.\n' + '\n' + 'Example:\n' + '\n' + ' >>> type Alias = 1/0\n' + ' >>> Alias.__value__\n' + ' Traceback (most recent call last):\n' + ' ...\n' + ' ZeroDivisionError: division by zero\n' + ' >>> def func[T: 1/0](): pass\n' + ' >>> T = func.__type_params__[0]\n' + ' >>> T.__bound__\n' + ' Traceback (most recent call last):\n' + ' ...\n' + ' ZeroDivisionError: division by zero\n' + '\n' + 'Here the exception is raised only when the "__value__" attribute ' + 'of\n' + 'the type alias or the "__bound__" attribute of the type variable ' + 'is\n' + 'accessed.\n' + '\n' + 'This behavior is primarily useful for references to types that ' + 'have\n' + 'not yet been defined when the type alias or type variable is ' + 'created.\n' + 'For example, lazy evaluation enables creation of mutually ' + 'recursive\n' + 'type aliases:\n' + '\n' + ' from typing import Literal\n' + '\n' + ' type SimpleExpr = int | Parenthesized\n' + ' type Parenthesized = tuple[Literal["("], Expr, Literal[")"]]\n' + ' type Expr = SimpleExpr | tuple[SimpleExpr, Literal["+", "-"], ' + 'Expr]\n' + '\n' + 'Lazily evaluated values are evaluated in annotation scope, which ' + 'means\n' + 'that names that appear inside the lazily evaluated value are ' + 'looked up\n' + 'as if they were used in the immediately enclosing scope.\n' + '\n' + 'Added in version 3.12.\n' + '\n' + '\n' + 'Builtins and restricted execution\n' + '=================================\n' + '\n' + '**CPython implementation detail:** Users should not touch\n' + '"__builtins__"; it is strictly an implementation detail. Users\n' + 'wanting to override values in the builtins namespace should ' + '"import"\n' + 'the "builtins" module and modify its attributes appropriately.\n' + '\n' + 'The builtins namespace associated with the execution of a code ' + 'block\n' + 'is actually found by looking up the name "__builtins__" in its ' + 'global\n' + 'namespace; this should be a dictionary or a module (in the latter ' + 'case\n' + 'the module’s dictionary is used). By default, when in the ' + '"__main__"\n' + 'module, "__builtins__" is the built-in module "builtins"; when in ' + 'any\n' + 'other module, "__builtins__" is an alias for the dictionary of ' + 'the\n' + '"builtins" module itself.\n' + '\n' + '\n' + 'Interaction with dynamic features\n' + '=================================\n' + '\n' + 'Name resolution of free variables occurs at runtime, not at ' + 'compile\n' + 'time. This means that the following code will print 42:\n' + '\n' + ' i = 10\n' + ' def f():\n' + ' print(i)\n' + ' i = 42\n' + ' f()\n' + '\n' + 'The "eval()" and "exec()" functions do not have access to the ' + 'full\n' + 'environment for resolving names. Names may be resolved in the ' + 'local\n' + 'and global namespaces of the caller. Free variables are not ' + 'resolved\n' + 'in the nearest enclosing namespace, but in the global namespace. ' + '[1]\n' + 'The "exec()" and "eval()" functions have optional arguments to\n' + 'override the global and local namespace. If only one namespace ' + 'is\n' + 'specified, it is used for both.\n', + 'nonlocal': 'The "nonlocal" statement\n' + '************************\n' + '\n' + ' nonlocal_stmt ::= "nonlocal" identifier ("," identifier)*\n' + '\n' + 'When the definition of a function or class is nested (enclosed) ' + 'within\n' + 'the definitions of other functions, its nonlocal scopes are the ' + 'local\n' + 'scopes of the enclosing functions. The "nonlocal" statement ' + 'causes the\n' + 'listed identifiers to refer to names previously bound in ' + 'nonlocal\n' + 'scopes. It allows encapsulated code to rebind such nonlocal\n' + 'identifiers. If a name is bound in more than one nonlocal ' + 'scope, the\n' + 'nearest binding is used. If a name is not bound in any nonlocal ' + 'scope,\n' + 'or if there is no nonlocal scope, a "SyntaxError" is raised.\n' + '\n' + 'The "nonlocal" statement applies to the entire scope of a ' + 'function or\n' + 'class body. A "SyntaxError" is raised if a variable is used or\n' + 'assigned to prior to its nonlocal declaration in the scope.\n' + '\n' + 'See also:\n' + '\n' + ' **PEP 3104** - Access to Names in Outer Scopes\n' + ' The specification for the "nonlocal" statement.\n' + '\n' + '**Programmer’s note:** "nonlocal" is a directive to the parser ' + 'and\n' + 'applies only to code parsed along with it. See the note for ' + 'the\n' + '"global" statement.\n', + 'numbers': 'Numeric literals\n' + '****************\n' + '\n' + 'There are three types of numeric literals: integers, ' + 'floating-point\n' + 'numbers, and imaginary numbers. There are no complex literals\n' + '(complex numbers can be formed by adding a real number and an\n' + 'imaginary number).\n' + '\n' + 'Note that numeric literals do not include a sign; a phrase like ' + '"-1"\n' + 'is actually an expression composed of the unary operator ‘"-"’ ' + 'and the\n' + 'literal "1".\n', + 'numeric-types': 'Emulating numeric types\n' + '***********************\n' + '\n' + 'The following methods can be defined to emulate numeric ' + 'objects.\n' + 'Methods corresponding to operations that are not supported ' + 'by the\n' + 'particular kind of number implemented (e.g., bitwise ' + 'operations for\n' + 'non-integral numbers) should be left undefined.\n' + '\n' + 'object.__add__(self, other)\n' + 'object.__sub__(self, other)\n' + 'object.__mul__(self, other)\n' + 'object.__matmul__(self, other)\n' + 'object.__truediv__(self, other)\n' + 'object.__floordiv__(self, other)\n' + 'object.__mod__(self, other)\n' + 'object.__divmod__(self, other)\n' + 'object.__pow__(self, other[, modulo])\n' + 'object.__lshift__(self, other)\n' + 'object.__rshift__(self, other)\n' + 'object.__and__(self, other)\n' + 'object.__xor__(self, other)\n' + 'object.__or__(self, other)\n' + '\n' + ' These methods are called to implement the binary ' + 'arithmetic\n' + ' operations ("+", "-", "*", "@", "/", "//", "%", ' + '"divmod()",\n' + ' "pow()", "**", "<<", ">>", "&", "^", "|"). For ' + 'instance, to\n' + ' evaluate the expression "x + y", where *x* is an ' + 'instance of a\n' + ' class that has an "__add__()" method, ' + '"type(x).__add__(x, y)" is\n' + ' called. The "__divmod__()" method should be the ' + 'equivalent to\n' + ' using "__floordiv__()" and "__mod__()"; it should not be ' + 'related to\n' + ' "__truediv__()". Note that "__pow__()" should be ' + 'defined to accept\n' + ' an optional third argument if the ternary version of the ' + 'built-in\n' + ' "pow()" function is to be supported.\n' + '\n' + ' If one of those methods does not support the operation ' + 'with the\n' + ' supplied arguments, it should return "NotImplemented".\n' + '\n' + 'object.__radd__(self, other)\n' + 'object.__rsub__(self, other)\n' + 'object.__rmul__(self, other)\n' + 'object.__rmatmul__(self, other)\n' + 'object.__rtruediv__(self, other)\n' + 'object.__rfloordiv__(self, other)\n' + 'object.__rmod__(self, other)\n' + 'object.__rdivmod__(self, other)\n' + 'object.__rpow__(self, other[, modulo])\n' + 'object.__rlshift__(self, other)\n' + 'object.__rrshift__(self, other)\n' + 'object.__rand__(self, other)\n' + 'object.__rxor__(self, other)\n' + 'object.__ror__(self, other)\n' + '\n' + ' These methods are called to implement the binary ' + 'arithmetic\n' + ' operations ("+", "-", "*", "@", "/", "//", "%", ' + '"divmod()",\n' + ' "pow()", "**", "<<", ">>", "&", "^", "|") with reflected ' + '(swapped)\n' + ' operands. These functions are only called if the left ' + 'operand does\n' + ' not support the corresponding operation [3] and the ' + 'operands are of\n' + ' different types. [4] For instance, to evaluate the ' + 'expression "x -\n' + ' y", where *y* is an instance of a class that has an ' + '"__rsub__()"\n' + ' method, "type(y).__rsub__(y, x)" is called if ' + '"type(x).__sub__(x,\n' + ' y)" returns "NotImplemented".\n' + '\n' + ' Note that ternary "pow()" will not try calling ' + '"__rpow__()" (the\n' + ' coercion rules would become too complicated).\n' + '\n' + ' Note:\n' + '\n' + ' If the right operand’s type is a subclass of the left ' + 'operand’s\n' + ' type and that subclass provides a different ' + 'implementation of the\n' + ' reflected method for the operation, this method will ' + 'be called\n' + ' before the left operand’s non-reflected method. This ' + 'behavior\n' + ' allows subclasses to override their ancestors’ ' + 'operations.\n' + '\n' + 'object.__iadd__(self, other)\n' + 'object.__isub__(self, other)\n' + 'object.__imul__(self, other)\n' + 'object.__imatmul__(self, other)\n' + 'object.__itruediv__(self, other)\n' + 'object.__ifloordiv__(self, other)\n' + 'object.__imod__(self, other)\n' + 'object.__ipow__(self, other[, modulo])\n' + 'object.__ilshift__(self, other)\n' + 'object.__irshift__(self, other)\n' + 'object.__iand__(self, other)\n' + 'object.__ixor__(self, other)\n' + 'object.__ior__(self, other)\n' + '\n' + ' These methods are called to implement the augmented ' + 'arithmetic\n' + ' assignments ("+=", "-=", "*=", "@=", "/=", "//=", "%=", ' + '"**=",\n' + ' "<<=", ">>=", "&=", "^=", "|="). These methods should ' + 'attempt to\n' + ' do the operation in-place (modifying *self*) and return ' + 'the result\n' + ' (which could be, but does not have to be, *self*). If a ' + 'specific\n' + ' method is not defined, or if that method returns ' + '"NotImplemented",\n' + ' the augmented assignment falls back to the normal ' + 'methods. For\n' + ' instance, if *x* is an instance of a class with an ' + '"__iadd__()"\n' + ' method, "x += y" is equivalent to "x = x.__iadd__(y)" . ' + 'If\n' + ' "__iadd__()" does not exist, or if "x.__iadd__(y)" ' + 'returns\n' + ' "NotImplemented", "x.__add__(y)" and "y.__radd__(x)" ' + 'are\n' + ' considered, as with the evaluation of "x + y". In ' + 'certain\n' + ' situations, augmented assignment can result in ' + 'unexpected errors\n' + ' (see Why does a_tuple[i] += [‘item’] raise an exception ' + 'when the\n' + ' addition works?), but this behavior is in fact part of ' + 'the data\n' + ' model.\n' + '\n' + 'object.__neg__(self)\n' + 'object.__pos__(self)\n' + 'object.__abs__(self)\n' + 'object.__invert__(self)\n' + '\n' + ' Called to implement the unary arithmetic operations ' + '("-", "+",\n' + ' "abs()" and "~").\n' + '\n' + 'object.__complex__(self)\n' + 'object.__int__(self)\n' + 'object.__float__(self)\n' + '\n' + ' Called to implement the built-in functions "complex()", ' + '"int()" and\n' + ' "float()". Should return a value of the appropriate ' + 'type.\n' + '\n' + 'object.__index__(self)\n' + '\n' + ' Called to implement "operator.index()", and whenever ' + 'Python needs\n' + ' to losslessly convert the numeric object to an integer ' + 'object (such\n' + ' as in slicing, or in the built-in "bin()", "hex()" and ' + '"oct()"\n' + ' functions). Presence of this method indicates that the ' + 'numeric\n' + ' object is an integer type. Must return an integer.\n' + '\n' + ' If "__int__()", "__float__()" and "__complex__()" are ' + 'not defined\n' + ' then corresponding built-in functions "int()", "float()" ' + 'and\n' + ' "complex()" fall back to "__index__()".\n' + '\n' + 'object.__round__(self[, ndigits])\n' + 'object.__trunc__(self)\n' + 'object.__floor__(self)\n' + 'object.__ceil__(self)\n' + '\n' + ' Called to implement the built-in function "round()" and ' + '"math"\n' + ' functions "trunc()", "floor()" and "ceil()". Unless ' + '*ndigits* is\n' + ' passed to "__round__()" all these methods should return ' + 'the value\n' + ' of the object truncated to an "Integral" (typically an ' + '"int").\n' + '\n' + ' The built-in function "int()" falls back to ' + '"__trunc__()" if\n' + ' neither "__int__()" nor "__index__()" is defined.\n' + '\n' + ' Changed in version 3.11: The delegation of "int()" to ' + '"__trunc__()"\n' + ' is deprecated.\n', + 'objects': 'Objects, values and types\n' + '*************************\n' + '\n' + '*Objects* are Python’s abstraction for data. All data in a ' + 'Python\n' + 'program is represented by objects or by relations between ' + 'objects. (In\n' + 'a sense, and in conformance to Von Neumann’s model of a “stored\n' + 'program computer”, code is also represented by objects.)\n' + '\n' + 'Every object has an identity, a type and a value. An object’s\n' + '*identity* never changes once it has been created; you may think ' + 'of it\n' + 'as the object’s address in memory. The "is" operator compares ' + 'the\n' + 'identity of two objects; the "id()" function returns an integer\n' + 'representing its identity.\n' + '\n' + '**CPython implementation detail:** For CPython, "id(x)" is the ' + 'memory\n' + 'address where "x" is stored.\n' + '\n' + 'An object’s type determines the operations that the object ' + 'supports\n' + '(e.g., “does it have a length?”) and also defines the possible ' + 'values\n' + 'for objects of that type. The "type()" function returns an ' + 'object’s\n' + 'type (which is an object itself). Like its identity, an ' + 'object’s\n' + '*type* is also unchangeable. [1]\n' + '\n' + 'The *value* of some objects can change. Objects whose value can\n' + 'change are said to be *mutable*; objects whose value is ' + 'unchangeable\n' + 'once they are created are called *immutable*. (The value of an\n' + 'immutable container object that contains a reference to a ' + 'mutable\n' + 'object can change when the latter’s value is changed; however ' + 'the\n' + 'container is still considered immutable, because the collection ' + 'of\n' + 'objects it contains cannot be changed. So, immutability is not\n' + 'strictly the same as having an unchangeable value, it is more ' + 'subtle.)\n' + 'An object’s mutability is determined by its type; for instance,\n' + 'numbers, strings and tuples are immutable, while dictionaries ' + 'and\n' + 'lists are mutable.\n' + '\n' + 'Objects are never explicitly destroyed; however, when they ' + 'become\n' + 'unreachable they may be garbage-collected. An implementation is\n' + 'allowed to postpone garbage collection or omit it altogether — it ' + 'is a\n' + 'matter of implementation quality how garbage collection is\n' + 'implemented, as long as no objects are collected that are still\n' + 'reachable.\n' + '\n' + '**CPython implementation detail:** CPython currently uses a ' + 'reference-\n' + 'counting scheme with (optional) delayed detection of cyclically ' + 'linked\n' + 'garbage, which collects most objects as soon as they become\n' + 'unreachable, but is not guaranteed to collect garbage containing\n' + 'circular references. See the documentation of the "gc" module ' + 'for\n' + 'information on controlling the collection of cyclic garbage. ' + 'Other\n' + 'implementations act differently and CPython may change. Do not ' + 'depend\n' + 'on immediate finalization of objects when they become unreachable ' + '(so\n' + 'you should always close files explicitly).\n' + '\n' + 'Note that the use of the implementation’s tracing or debugging\n' + 'facilities may keep objects alive that would normally be ' + 'collectable.\n' + 'Also note that catching an exception with a "try"…"except" ' + 'statement\n' + 'may keep objects alive.\n' + '\n' + 'Some objects contain references to “external” resources such as ' + 'open\n' + 'files or windows. It is understood that these resources are ' + 'freed\n' + 'when the object is garbage-collected, but since garbage ' + 'collection is\n' + 'not guaranteed to happen, such objects also provide an explicit ' + 'way to\n' + 'release the external resource, usually a "close()" method. ' + 'Programs\n' + 'are strongly recommended to explicitly close such objects. The\n' + '"try"…"finally" statement and the "with" statement provide ' + 'convenient\n' + 'ways to do this.\n' + '\n' + 'Some objects contain references to other objects; these are ' + 'called\n' + '*containers*. Examples of containers are tuples, lists and\n' + 'dictionaries. The references are part of a container’s value. ' + 'In\n' + 'most cases, when we talk about the value of a container, we imply ' + 'the\n' + 'values, not the identities of the contained objects; however, ' + 'when we\n' + 'talk about the mutability of a container, only the identities of ' + 'the\n' + 'immediately contained objects are implied. So, if an immutable\n' + 'container (like a tuple) contains a reference to a mutable ' + 'object, its\n' + 'value changes if that mutable object is changed.\n' + '\n' + 'Types affect almost all aspects of object behavior. Even the\n' + 'importance of object identity is affected in some sense: for ' + 'immutable\n' + 'types, operations that compute new values may actually return a\n' + 'reference to any existing object with the same type and value, ' + 'while\n' + 'for mutable objects this is not allowed. For example, after "a = ' + '1; b\n' + '= 1", *a* and *b* may or may not refer to the same object with ' + 'the\n' + 'value one, depending on the implementation. This is because "int" ' + 'is\n' + 'an immutable type, so the reference to "1" can be reused. This\n' + 'behaviour depends on the implementation used, so should not be ' + 'relied\n' + 'upon, but is something to be aware of when making use of object\n' + 'identity tests. However, after "c = []; d = []", *c* and *d* are\n' + 'guaranteed to refer to two different, unique, newly created ' + 'empty\n' + 'lists. (Note that "e = f = []" assigns the *same* object to both ' + '*e*\n' + 'and *f*.)\n', + 'operator-summary': 'Operator precedence\n' + '*******************\n' + '\n' + 'The following table summarizes the operator precedence ' + 'in Python, from\n' + 'highest precedence (most binding) to lowest precedence ' + '(least\n' + 'binding). Operators in the same box have the same ' + 'precedence. Unless\n' + 'the syntax is explicitly given, operators are binary. ' + 'Operators in\n' + 'the same box group left to right (except for ' + 'exponentiation and\n' + 'conditional expressions, which group from right to ' + 'left).\n' + '\n' + 'Note that comparisons, membership tests, and identity ' + 'tests, all have\n' + 'the same precedence and have a left-to-right chaining ' + 'feature as\n' + 'described in the Comparisons section.\n' + '\n' + '+-------------------------------------------------+---------------------------------------+\n' + '| Operator | ' + 'Description |\n' + '|=================================================|=======================================|\n' + '| "(expressions...)", "[expressions...]", "{key: | ' + 'Binding or parenthesized expression, |\n' + '| value...}", "{expressions...}" | list ' + 'display, dictionary display, set |\n' + '| | ' + 'display |\n' + '+-------------------------------------------------+---------------------------------------+\n' + '| "x[index]", "x[index:index]", | ' + 'Subscription, slicing, call, |\n' + '| "x(arguments...)", "x.attribute" | ' + 'attribute reference |\n' + '+-------------------------------------------------+---------------------------------------+\n' + '| "await x" | ' + 'Await expression |\n' + '+-------------------------------------------------+---------------------------------------+\n' + '| "**" | ' + 'Exponentiation [5] |\n' + '+-------------------------------------------------+---------------------------------------+\n' + '| "+x", "-x", "~x" | ' + 'Positive, negative, bitwise NOT |\n' + '+-------------------------------------------------+---------------------------------------+\n' + '| "*", "@", "/", "//", "%" | ' + 'Multiplication, matrix |\n' + '| | ' + 'multiplication, division, floor |\n' + '| | ' + 'division, remainder [6] |\n' + '+-------------------------------------------------+---------------------------------------+\n' + '| "+", "-" | ' + 'Addition and subtraction |\n' + '+-------------------------------------------------+---------------------------------------+\n' + '| "<<", ">>" | ' + 'Shifts |\n' + '+-------------------------------------------------+---------------------------------------+\n' + '| "&" | ' + 'Bitwise AND |\n' + '+-------------------------------------------------+---------------------------------------+\n' + '| "^" | ' + 'Bitwise XOR |\n' + '+-------------------------------------------------+---------------------------------------+\n' + '| "|" | ' + 'Bitwise OR |\n' + '+-------------------------------------------------+---------------------------------------+\n' + '| "in", "not in", "is", "is not", "<", "<=", ">", | ' + 'Comparisons, including membership |\n' + '| ">=", "!=", "==" | ' + 'tests and identity tests |\n' + '+-------------------------------------------------+---------------------------------------+\n' + '| "not x" | ' + 'Boolean NOT |\n' + '+-------------------------------------------------+---------------------------------------+\n' + '| "and" | ' + 'Boolean AND |\n' + '+-------------------------------------------------+---------------------------------------+\n' + '| "or" | ' + 'Boolean OR |\n' + '+-------------------------------------------------+---------------------------------------+\n' + '| "if" – "else" | ' + 'Conditional expression |\n' + '+-------------------------------------------------+---------------------------------------+\n' + '| "lambda" | ' + 'Lambda expression |\n' + '+-------------------------------------------------+---------------------------------------+\n' + '| ":=" | ' + 'Assignment expression |\n' + '+-------------------------------------------------+---------------------------------------+\n' + '\n' + '-[ Footnotes ]-\n' + '\n' + '[1] While "abs(x%y) < abs(y)" is true mathematically, ' + 'for floats it\n' + ' may not be true numerically due to roundoff. For ' + 'example, and\n' + ' assuming a platform on which a Python float is an ' + 'IEEE 754 double-\n' + ' precision number, in order that "-1e-100 % 1e100" ' + 'have the same\n' + ' sign as "1e100", the computed result is "-1e-100 + ' + '1e100", which\n' + ' is numerically exactly equal to "1e100". The ' + 'function\n' + ' "math.fmod()" returns a result whose sign matches ' + 'the sign of the\n' + ' first argument instead, and so returns "-1e-100" in ' + 'this case.\n' + ' Which approach is more appropriate depends on the ' + 'application.\n' + '\n' + '[2] If x is very close to an exact integer multiple of ' + 'y, it’s\n' + ' possible for "x//y" to be one larger than ' + '"(x-x%y)//y" due to\n' + ' rounding. In such cases, Python returns the latter ' + 'result, in\n' + ' order to preserve that "divmod(x,y)[0] * y + x % y" ' + 'be very close\n' + ' to "x".\n' + '\n' + '[3] The Unicode standard distinguishes between *code ' + 'points* (e.g.\n' + ' U+0041) and *abstract characters* (e.g. “LATIN ' + 'CAPITAL LETTER A”).\n' + ' While most abstract characters in Unicode are only ' + 'represented\n' + ' using one code point, there is a number of abstract ' + 'characters\n' + ' that can in addition be represented using a sequence ' + 'of more than\n' + ' one code point. For example, the abstract character ' + '“LATIN\n' + ' CAPITAL LETTER C WITH CEDILLA” can be represented as ' + 'a single\n' + ' *precomposed character* at code position U+00C7, or ' + 'as a sequence\n' + ' of a *base character* at code position U+0043 (LATIN ' + 'CAPITAL\n' + ' LETTER C), followed by a *combining character* at ' + 'code position\n' + ' U+0327 (COMBINING CEDILLA).\n' + '\n' + ' The comparison operators on strings compare at the ' + 'level of\n' + ' Unicode code points. This may be counter-intuitive ' + 'to humans. For\n' + ' example, ""\\u00C7" == "\\u0043\\u0327"" is "False", ' + 'even though both\n' + ' strings represent the same abstract character “LATIN ' + 'CAPITAL\n' + ' LETTER C WITH CEDILLA”.\n' + '\n' + ' To compare strings at the level of abstract ' + 'characters (that is,\n' + ' in a way intuitive to humans), use ' + '"unicodedata.normalize()".\n' + '\n' + '[4] Due to automatic garbage-collection, free lists, and ' + 'the dynamic\n' + ' nature of descriptors, you may notice seemingly ' + 'unusual behaviour\n' + ' in certain uses of the "is" operator, like those ' + 'involving\n' + ' comparisons between instance methods, or constants. ' + 'Check their\n' + ' documentation for more info.\n' + '\n' + '[5] The power operator "**" binds less tightly than an ' + 'arithmetic or\n' + ' bitwise unary operator on its right, that is, ' + '"2**-1" is "0.5".\n' + '\n' + '[6] The "%" operator is also used for string formatting; ' + 'the same\n' + ' precedence applies.\n', + 'pass': 'The "pass" statement\n' + '********************\n' + '\n' + ' pass_stmt ::= "pass"\n' + '\n' + '"pass" is a null operation — when it is executed, nothing happens. ' + 'It\n' + 'is useful as a placeholder when a statement is required ' + 'syntactically,\n' + 'but no code needs to be executed, for example:\n' + '\n' + ' def f(arg): pass # a function that does nothing (yet)\n' + '\n' + ' class C: pass # a class with no methods (yet)\n', + 'power': 'The power operator\n' + '******************\n' + '\n' + 'The power operator binds more tightly than unary operators on its\n' + 'left; it binds less tightly than unary operators on its right. ' + 'The\n' + 'syntax is:\n' + '\n' + ' power ::= (await_expr | primary) ["**" u_expr]\n' + '\n' + 'Thus, in an unparenthesized sequence of power and unary operators, ' + 'the\n' + 'operators are evaluated from right to left (this does not ' + 'constrain\n' + 'the evaluation order for the operands): "-1**2" results in "-1".\n' + '\n' + 'The power operator has the same semantics as the built-in "pow()"\n' + 'function, when called with two arguments: it yields its left ' + 'argument\n' + 'raised to the power of its right argument. The numeric arguments ' + 'are\n' + 'first converted to a common type, and the result is of that type.\n' + '\n' + 'For int operands, the result has the same type as the operands ' + 'unless\n' + 'the second argument is negative; in that case, all arguments are\n' + 'converted to float and a float result is delivered. For example,\n' + '"10**2" returns "100", but "10**-2" returns "0.01".\n' + '\n' + 'Raising "0.0" to a negative power results in a ' + '"ZeroDivisionError".\n' + 'Raising a negative number to a fractional power results in a ' + '"complex"\n' + 'number. (In earlier versions it raised a "ValueError".)\n' + '\n' + 'This operation can be customized using the special "__pow__()" and\n' + '"__rpow__()" methods.\n', + 'raise': 'The "raise" statement\n' + '*********************\n' + '\n' + ' raise_stmt ::= "raise" [expression ["from" expression]]\n' + '\n' + 'If no expressions are present, "raise" re-raises the exception that ' + 'is\n' + 'currently being handled, which is also known as the *active\n' + 'exception*. If there isn’t currently an active exception, a\n' + '"RuntimeError" exception is raised indicating that this is an ' + 'error.\n' + '\n' + 'Otherwise, "raise" evaluates the first expression as the exception\n' + 'object. It must be either a subclass or an instance of\n' + '"BaseException". If it is a class, the exception instance will be\n' + 'obtained when needed by instantiating the class with no arguments.\n' + '\n' + 'The *type* of the exception is the exception instance’s class, the\n' + '*value* is the instance itself.\n' + '\n' + 'A traceback object is normally created automatically when an ' + 'exception\n' + 'is raised and attached to it as the "__traceback__" attribute. You ' + 'can\n' + 'create an exception and set your own traceback in one step using ' + 'the\n' + '"with_traceback()" exception method (which returns the same ' + 'exception\n' + 'instance, with its traceback set to its argument), like so:\n' + '\n' + ' raise Exception("foo occurred").with_traceback(tracebackobj)\n' + '\n' + 'The "from" clause is used for exception chaining: if given, the ' + 'second\n' + '*expression* must be another exception class or instance. If the\n' + 'second expression is an exception instance, it will be attached to ' + 'the\n' + 'raised exception as the "__cause__" attribute (which is writable). ' + 'If\n' + 'the expression is an exception class, the class will be ' + 'instantiated\n' + 'and the resulting exception instance will be attached to the ' + 'raised\n' + 'exception as the "__cause__" attribute. If the raised exception is ' + 'not\n' + 'handled, both exceptions will be printed:\n' + '\n' + ' >>> try:\n' + ' ... print(1 / 0)\n' + ' ... except Exception as exc:\n' + ' ... raise RuntimeError("Something bad happened") from exc\n' + ' ...\n' + ' Traceback (most recent call last):\n' + ' File "", line 2, in \n' + ' print(1 / 0)\n' + ' ~~^~~\n' + ' ZeroDivisionError: division by zero\n' + '\n' + ' The above exception was the direct cause of the following ' + 'exception:\n' + '\n' + ' Traceback (most recent call last):\n' + ' File "", line 4, in \n' + ' raise RuntimeError("Something bad happened") from exc\n' + ' RuntimeError: Something bad happened\n' + '\n' + 'A similar mechanism works implicitly if a new exception is raised ' + 'when\n' + 'an exception is already being handled. An exception may be ' + 'handled\n' + 'when an "except" or "finally" clause, or a "with" statement, is ' + 'used.\n' + 'The previous exception is then attached as the new exception’s\n' + '"__context__" attribute:\n' + '\n' + ' >>> try:\n' + ' ... print(1 / 0)\n' + ' ... except:\n' + ' ... raise RuntimeError("Something bad happened")\n' + ' ...\n' + ' Traceback (most recent call last):\n' + ' File "", line 2, in \n' + ' print(1 / 0)\n' + ' ~~^~~\n' + ' ZeroDivisionError: division by zero\n' + '\n' + ' During handling of the above exception, another exception ' + 'occurred:\n' + '\n' + ' Traceback (most recent call last):\n' + ' File "", line 4, in \n' + ' raise RuntimeError("Something bad happened")\n' + ' RuntimeError: Something bad happened\n' + '\n' + 'Exception chaining can be explicitly suppressed by specifying ' + '"None"\n' + 'in the "from" clause:\n' + '\n' + ' >>> try:\n' + ' ... print(1 / 0)\n' + ' ... except:\n' + ' ... raise RuntimeError("Something bad happened") from None\n' + ' ...\n' + ' Traceback (most recent call last):\n' + ' File "", line 4, in \n' + ' RuntimeError: Something bad happened\n' + '\n' + 'Additional information on exceptions can be found in section\n' + 'Exceptions, and information about handling exceptions is in ' + 'section\n' + 'The try statement.\n' + '\n' + 'Changed in version 3.3: "None" is now permitted as "Y" in "raise X\n' + 'from Y".Added the "__suppress_context__" attribute to suppress\n' + 'automatic display of the exception context.\n' + '\n' + 'Changed in version 3.11: If the traceback of the active exception ' + 'is\n' + 'modified in an "except" clause, a subsequent "raise" statement re-\n' + 'raises the exception with the modified traceback. Previously, the\n' + 'exception was re-raised with the traceback it had when it was ' + 'caught.\n', + 'return': 'The "return" statement\n' + '**********************\n' + '\n' + ' return_stmt ::= "return" [expression_list]\n' + '\n' + '"return" may only occur syntactically nested in a function ' + 'definition,\n' + 'not within a nested class definition.\n' + '\n' + 'If an expression list is present, it is evaluated, else "None" is\n' + 'substituted.\n' + '\n' + '"return" leaves the current function call with the expression list ' + '(or\n' + '"None") as return value.\n' + '\n' + 'When "return" passes control out of a "try" statement with a ' + '"finally"\n' + 'clause, that "finally" clause is executed before really leaving ' + 'the\n' + 'function.\n' + '\n' + 'In a generator function, the "return" statement indicates that ' + 'the\n' + 'generator is done and will cause "StopIteration" to be raised. ' + 'The\n' + 'returned value (if any) is used as an argument to construct\n' + '"StopIteration" and becomes the "StopIteration.value" attribute.\n' + '\n' + 'In an asynchronous generator function, an empty "return" ' + 'statement\n' + 'indicates that the asynchronous generator is done and will cause\n' + '"StopAsyncIteration" to be raised. A non-empty "return" statement ' + 'is\n' + 'a syntax error in an asynchronous generator function.\n', + 'sequence-types': 'Emulating container types\n' + '*************************\n' + '\n' + 'The following methods can be defined to implement ' + 'container objects.\n' + 'None of them are provided by the "object" class itself. ' + 'Containers\n' + 'usually are *sequences* (such as "lists" or "tuples") or ' + '*mappings*\n' + '(like *dictionaries*), but can represent other containers ' + 'as well.\n' + 'The first set of methods is used either to emulate a ' + 'sequence or to\n' + 'emulate a mapping; the difference is that for a sequence, ' + 'the\n' + 'allowable keys should be the integers *k* for which "0 <= ' + 'k < N" where\n' + '*N* is the length of the sequence, or "slice" objects, ' + 'which define a\n' + 'range of items. It is also recommended that mappings ' + 'provide the\n' + 'methods "keys()", "values()", "items()", "get()", ' + '"clear()",\n' + '"setdefault()", "pop()", "popitem()", "copy()", and ' + '"update()"\n' + 'behaving similar to those for Python’s standard ' + '"dictionary" objects.\n' + 'The "collections.abc" module provides a "MutableMapping" ' + '*abstract\n' + 'base class* to help create those methods from a base set ' + 'of\n' + '"__getitem__()", "__setitem__()", "__delitem__()", and ' + '"keys()".\n' + 'Mutable sequences should provide methods "append()", ' + '"count()",\n' + '"index()", "extend()", "insert()", "pop()", "remove()", ' + '"reverse()"\n' + 'and "sort()", like Python standard "list" objects. ' + 'Finally, sequence\n' + 'types should implement addition (meaning concatenation) ' + 'and\n' + 'multiplication (meaning repetition) by defining the ' + 'methods\n' + '"__add__()", "__radd__()", "__iadd__()", "__mul__()", ' + '"__rmul__()" and\n' + '"__imul__()" described below; they should not define other ' + 'numerical\n' + 'operators. It is recommended that both mappings and ' + 'sequences\n' + 'implement the "__contains__()" method to allow efficient ' + 'use of the\n' + '"in" operator; for mappings, "in" should search the ' + 'mapping’s keys;\n' + 'for sequences, it should search through the values. It is ' + 'further\n' + 'recommended that both mappings and sequences implement ' + 'the\n' + '"__iter__()" method to allow efficient iteration through ' + 'the\n' + 'container; for mappings, "__iter__()" should iterate ' + 'through the\n' + 'object’s keys; for sequences, it should iterate through ' + 'the values.\n' + '\n' + 'object.__len__(self)\n' + '\n' + ' Called to implement the built-in function "len()". ' + 'Should return\n' + ' the length of the object, an integer ">=" 0. Also, an ' + 'object that\n' + ' doesn’t define a "__bool__()" method and whose ' + '"__len__()" method\n' + ' returns zero is considered to be false in a Boolean ' + 'context.\n' + '\n' + ' **CPython implementation detail:** In CPython, the ' + 'length is\n' + ' required to be at most "sys.maxsize". If the length is ' + 'larger than\n' + ' "sys.maxsize" some features (such as "len()") may ' + 'raise\n' + ' "OverflowError". To prevent raising "OverflowError" by ' + 'truth value\n' + ' testing, an object must define a "__bool__()" method.\n' + '\n' + 'object.__length_hint__(self)\n' + '\n' + ' Called to implement "operator.length_hint()". Should ' + 'return an\n' + ' estimated length for the object (which may be greater ' + 'or less than\n' + ' the actual length). The length must be an integer ">=" ' + '0. The\n' + ' return value may also be "NotImplemented", which is ' + 'treated the\n' + ' same as if the "__length_hint__" method didn’t exist at ' + 'all. This\n' + ' method is purely an optimization and is never required ' + 'for\n' + ' correctness.\n' + '\n' + ' Added in version 3.4.\n' + '\n' + 'Note:\n' + '\n' + ' Slicing is done exclusively with the following three ' + 'methods. A\n' + ' call like\n' + '\n' + ' a[1:2] = b\n' + '\n' + ' is translated to\n' + '\n' + ' a[slice(1, 2, None)] = b\n' + '\n' + ' and so forth. Missing slice items are always filled in ' + 'with "None".\n' + '\n' + 'object.__getitem__(self, key)\n' + '\n' + ' Called to implement evaluation of "self[key]". For ' + '*sequence*\n' + ' types, the accepted keys should be integers. ' + 'Optionally, they may\n' + ' support "slice" objects as well. Negative index ' + 'support is also\n' + ' optional. If *key* is of an inappropriate type, ' + '"TypeError" may be\n' + ' raised; if *key* is a value outside the set of indexes ' + 'for the\n' + ' sequence (after any special interpretation of negative ' + 'values),\n' + ' "IndexError" should be raised. For *mapping* types, if ' + '*key* is\n' + ' missing (not in the container), "KeyError" should be ' + 'raised.\n' + '\n' + ' Note:\n' + '\n' + ' "for" loops expect that an "IndexError" will be ' + 'raised for\n' + ' illegal indexes to allow proper detection of the end ' + 'of the\n' + ' sequence.\n' + '\n' + ' Note:\n' + '\n' + ' When subscripting a *class*, the special class ' + 'method\n' + ' "__class_getitem__()" may be called instead of ' + '"__getitem__()".\n' + ' See __class_getitem__ versus __getitem__ for more ' + 'details.\n' + '\n' + 'object.__setitem__(self, key, value)\n' + '\n' + ' Called to implement assignment to "self[key]". Same ' + 'note as for\n' + ' "__getitem__()". This should only be implemented for ' + 'mappings if\n' + ' the objects support changes to the values for keys, or ' + 'if new keys\n' + ' can be added, or for sequences if elements can be ' + 'replaced. The\n' + ' same exceptions should be raised for improper *key* ' + 'values as for\n' + ' the "__getitem__()" method.\n' + '\n' + 'object.__delitem__(self, key)\n' + '\n' + ' Called to implement deletion of "self[key]". Same note ' + 'as for\n' + ' "__getitem__()". This should only be implemented for ' + 'mappings if\n' + ' the objects support removal of keys, or for sequences ' + 'if elements\n' + ' can be removed from the sequence. The same exceptions ' + 'should be\n' + ' raised for improper *key* values as for the ' + '"__getitem__()" method.\n' + '\n' + 'object.__missing__(self, key)\n' + '\n' + ' Called by "dict"."__getitem__()" to implement ' + '"self[key]" for dict\n' + ' subclasses when key is not in the dictionary.\n' + '\n' + 'object.__iter__(self)\n' + '\n' + ' This method is called when an *iterator* is required ' + 'for a\n' + ' container. This method should return a new iterator ' + 'object that can\n' + ' iterate over all the objects in the container. For ' + 'mappings, it\n' + ' should iterate over the keys of the container.\n' + '\n' + 'object.__reversed__(self)\n' + '\n' + ' Called (if present) by the "reversed()" built-in to ' + 'implement\n' + ' reverse iteration. It should return a new iterator ' + 'object that\n' + ' iterates over all the objects in the container in ' + 'reverse order.\n' + '\n' + ' If the "__reversed__()" method is not provided, the ' + '"reversed()"\n' + ' built-in will fall back to using the sequence protocol ' + '("__len__()"\n' + ' and "__getitem__()"). Objects that support the ' + 'sequence protocol\n' + ' should only provide "__reversed__()" if they can ' + 'provide an\n' + ' implementation that is more efficient than the one ' + 'provided by\n' + ' "reversed()".\n' + '\n' + 'The membership test operators ("in" and "not in") are ' + 'normally\n' + 'implemented as an iteration through a container. However, ' + 'container\n' + 'objects can supply the following special method with a ' + 'more efficient\n' + 'implementation, which also does not require the object be ' + 'iterable.\n' + '\n' + 'object.__contains__(self, item)\n' + '\n' + ' Called to implement membership test operators. Should ' + 'return true\n' + ' if *item* is in *self*, false otherwise. For mapping ' + 'objects, this\n' + ' should consider the keys of the mapping rather than the ' + 'values or\n' + ' the key-item pairs.\n' + '\n' + ' For objects that don’t define "__contains__()", the ' + 'membership test\n' + ' first tries iteration via "__iter__()", then the old ' + 'sequence\n' + ' iteration protocol via "__getitem__()", see this ' + 'section in the\n' + ' language reference.\n', + 'shifting': 'Shifting operations\n' + '*******************\n' + '\n' + 'The shifting operations have lower priority than the arithmetic\n' + 'operations:\n' + '\n' + ' shift_expr ::= a_expr | shift_expr ("<<" | ">>") a_expr\n' + '\n' + 'These operators accept integers as arguments. They shift the ' + 'first\n' + 'argument to the left or right by the number of bits given by ' + 'the\n' + 'second argument.\n' + '\n' + 'The left shift operation can be customized using the special\n' + '"__lshift__()" and "__rlshift__()" methods. The right shift ' + 'operation\n' + 'can be customized using the special "__rshift__()" and ' + '"__rrshift__()"\n' + 'methods.\n' + '\n' + 'A right shift by *n* bits is defined as floor division by ' + '"pow(2,n)".\n' + 'A left shift by *n* bits is defined as multiplication with ' + '"pow(2,n)".\n', + 'slicings': 'Slicings\n' + '********\n' + '\n' + 'A slicing selects a range of items in a sequence object (e.g., ' + 'a\n' + 'string, tuple or list). Slicings may be used as expressions or ' + 'as\n' + 'targets in assignment or "del" statements. The syntax for a ' + 'slicing:\n' + '\n' + ' slicing ::= primary "[" slice_list "]"\n' + ' slice_list ::= slice_item ("," slice_item)* [","]\n' + ' slice_item ::= expression | proper_slice\n' + ' proper_slice ::= [lower_bound] ":" [upper_bound] [ ":" ' + '[stride] ]\n' + ' lower_bound ::= expression\n' + ' upper_bound ::= expression\n' + ' stride ::= expression\n' + '\n' + 'There is ambiguity in the formal syntax here: anything that ' + 'looks like\n' + 'an expression list also looks like a slice list, so any ' + 'subscription\n' + 'can be interpreted as a slicing. Rather than further ' + 'complicating the\n' + 'syntax, this is disambiguated by defining that in this case the\n' + 'interpretation as a subscription takes priority over the\n' + 'interpretation as a slicing (this is the case if the slice list\n' + 'contains no proper slice).\n' + '\n' + 'The semantics for a slicing are as follows. The primary is ' + 'indexed\n' + '(using the same "__getitem__()" method as normal subscription) ' + 'with a\n' + 'key that is constructed from the slice list, as follows. If the ' + 'slice\n' + 'list contains at least one comma, the key is a tuple containing ' + 'the\n' + 'conversion of the slice items; otherwise, the conversion of the ' + 'lone\n' + 'slice item is the key. The conversion of a slice item that is ' + 'an\n' + 'expression is that expression. The conversion of a proper slice ' + 'is a\n' + 'slice object (see section The standard type hierarchy) whose ' + '"start",\n' + '"stop" and "step" attributes are the values of the expressions ' + 'given\n' + 'as lower bound, upper bound and stride, respectively, ' + 'substituting\n' + '"None" for missing expressions.\n', + 'specialattrs': 'Special Attributes\n' + '******************\n' + '\n' + 'The implementation adds a few special read-only attributes ' + 'to several\n' + 'object types, where they are relevant. Some of these are ' + 'not reported\n' + 'by the "dir()" built-in function.\n' + '\n' + 'definition.__name__\n' + '\n' + ' The name of the class, function, method, descriptor, or ' + 'generator\n' + ' instance.\n' + '\n' + 'definition.__qualname__\n' + '\n' + ' The *qualified name* of the class, function, method, ' + 'descriptor, or\n' + ' generator instance.\n' + '\n' + ' Added in version 3.3.\n' + '\n' + 'definition.__module__\n' + '\n' + ' The name of the module in which a class or function was ' + 'defined.\n' + '\n' + 'definition.__doc__\n' + '\n' + ' The documentation string of a class or function, or ' + '"None" if\n' + ' undefined.\n' + '\n' + 'definition.__type_params__\n' + '\n' + ' The type parameters of generic classes, functions, and ' + 'type\n' + ' aliases. For classes and functions that are not generic, ' + 'this will\n' + ' be an empty tuple.\n' + '\n' + ' Added in version 3.12.\n', + 'specialnames': 'Special method names\n' + '********************\n' + '\n' + 'A class can implement certain operations that are invoked by ' + 'special\n' + 'syntax (such as arithmetic operations or subscripting and ' + 'slicing) by\n' + 'defining methods with special names. This is Python’s ' + 'approach to\n' + '*operator overloading*, allowing classes to define their own ' + 'behavior\n' + 'with respect to language operators. For instance, if a ' + 'class defines\n' + 'a method named "__getitem__()", and "x" is an instance of ' + 'this class,\n' + 'then "x[i]" is roughly equivalent to "type(x).__getitem__(x, ' + 'i)".\n' + 'Except where mentioned, attempts to execute an operation ' + 'raise an\n' + 'exception when no appropriate method is defined (typically\n' + '"AttributeError" or "TypeError").\n' + '\n' + 'Setting a special method to "None" indicates that the ' + 'corresponding\n' + 'operation is not available. For example, if a class sets ' + '"__iter__()"\n' + 'to "None", the class is not iterable, so calling "iter()" on ' + 'its\n' + 'instances will raise a "TypeError" (without falling back to\n' + '"__getitem__()"). [2]\n' + '\n' + 'When implementing a class that emulates any built-in type, ' + 'it is\n' + 'important that the emulation only be implemented to the ' + 'degree that it\n' + 'makes sense for the object being modelled. For example, ' + 'some\n' + 'sequences may work well with retrieval of individual ' + 'elements, but\n' + 'extracting a slice may not make sense. (One example of this ' + 'is the\n' + '"NodeList" interface in the W3C’s Document Object Model.)\n' + '\n' + '\n' + 'Basic customization\n' + '===================\n' + '\n' + 'object.__new__(cls[, ...])\n' + '\n' + ' Called to create a new instance of class *cls*. ' + '"__new__()" is a\n' + ' static method (special-cased so you need not declare it ' + 'as such)\n' + ' that takes the class of which an instance was requested ' + 'as its\n' + ' first argument. The remaining arguments are those passed ' + 'to the\n' + ' object constructor expression (the call to the class). ' + 'The return\n' + ' value of "__new__()" should be the new object instance ' + '(usually an\n' + ' instance of *cls*).\n' + '\n' + ' Typical implementations create a new instance of the ' + 'class by\n' + ' invoking the superclass’s "__new__()" method using\n' + ' "super().__new__(cls[, ...])" with appropriate arguments ' + 'and then\n' + ' modifying the newly created instance as necessary before ' + 'returning\n' + ' it.\n' + '\n' + ' If "__new__()" is invoked during object construction and ' + 'it returns\n' + ' an instance of *cls*, then the new instance’s ' + '"__init__()" method\n' + ' will be invoked like "__init__(self[, ...])", where ' + '*self* is the\n' + ' new instance and the remaining arguments are the same as ' + 'were\n' + ' passed to the object constructor.\n' + '\n' + ' If "__new__()" does not return an instance of *cls*, then ' + 'the new\n' + ' instance’s "__init__()" method will not be invoked.\n' + '\n' + ' "__new__()" is intended mainly to allow subclasses of ' + 'immutable\n' + ' types (like int, str, or tuple) to customize instance ' + 'creation. It\n' + ' is also commonly overridden in custom metaclasses in ' + 'order to\n' + ' customize class creation.\n' + '\n' + 'object.__init__(self[, ...])\n' + '\n' + ' Called after the instance has been created (by ' + '"__new__()"), but\n' + ' before it is returned to the caller. The arguments are ' + 'those\n' + ' passed to the class constructor expression. If a base ' + 'class has an\n' + ' "__init__()" method, the derived class’s "__init__()" ' + 'method, if\n' + ' any, must explicitly call it to ensure proper ' + 'initialization of the\n' + ' base class part of the instance; for example:\n' + ' "super().__init__([args...])".\n' + '\n' + ' Because "__new__()" and "__init__()" work together in ' + 'constructing\n' + ' objects ("__new__()" to create it, and "__init__()" to ' + 'customize\n' + ' it), no non-"None" value may be returned by "__init__()"; ' + 'doing so\n' + ' will cause a "TypeError" to be raised at runtime.\n' + '\n' + 'object.__del__(self)\n' + '\n' + ' Called when the instance is about to be destroyed. This ' + 'is also\n' + ' called a finalizer or (improperly) a destructor. If a ' + 'base class\n' + ' has a "__del__()" method, the derived class’s "__del__()" ' + 'method,\n' + ' if any, must explicitly call it to ensure proper deletion ' + 'of the\n' + ' base class part of the instance.\n' + '\n' + ' It is possible (though not recommended!) for the ' + '"__del__()" method\n' + ' to postpone destruction of the instance by creating a new ' + 'reference\n' + ' to it. This is called object *resurrection*. It is\n' + ' implementation-dependent whether "__del__()" is called a ' + 'second\n' + ' time when a resurrected object is about to be destroyed; ' + 'the\n' + ' current *CPython* implementation only calls it once.\n' + '\n' + ' It is not guaranteed that "__del__()" methods are called ' + 'for\n' + ' objects that still exist when the interpreter exits.\n' + ' "weakref.finalize" provides a straightforward way to ' + 'register a\n' + ' cleanup function to be called when an object is garbage ' + 'collected.\n' + '\n' + ' Note:\n' + '\n' + ' "del x" doesn’t directly call "x.__del__()" — the ' + 'former\n' + ' decrements the reference count for "x" by one, and the ' + 'latter is\n' + ' only called when "x"’s reference count reaches zero.\n' + '\n' + ' **CPython implementation detail:** It is possible for a ' + 'reference\n' + ' cycle to prevent the reference count of an object from ' + 'going to\n' + ' zero. In this case, the cycle will be later detected and ' + 'deleted\n' + ' by the *cyclic garbage collector*. A common cause of ' + 'reference\n' + ' cycles is when an exception has been caught in a local ' + 'variable.\n' + ' The frame’s locals then reference the exception, which ' + 'references\n' + ' its own traceback, which references the locals of all ' + 'frames caught\n' + ' in the traceback.\n' + '\n' + ' See also: Documentation for the "gc" module.\n' + '\n' + ' Warning:\n' + '\n' + ' Due to the precarious circumstances under which ' + '"__del__()"\n' + ' methods are invoked, exceptions that occur during their ' + 'execution\n' + ' are ignored, and a warning is printed to "sys.stderr" ' + 'instead.\n' + ' In particular:\n' + '\n' + ' * "__del__()" can be invoked when arbitrary code is ' + 'being\n' + ' executed, including from any arbitrary thread. If ' + '"__del__()"\n' + ' needs to take a lock or invoke any other blocking ' \ + 'resource, it\n' + ' may deadlock as the resource may already be taken by ' + 'the code\n' + ' that gets interrupted to execute "__del__()".\n' + '\n' \ + ' * "__del__()" can be executed during interpreter ' + 'shutdown. As a\n' \ + ' consequence, the global variables it needs to access ' \ + '(including\n' + ' other modules) may already have been deleted or set ' + 'to "None".\n' + ' Python guarantees that globals whose name begins with ' \ + 'a single\n' + ' underscore are deleted from their module before other ' + 'globals\n' + ' are deleted; if no other references to such globals ' + 'exist, this\n' + ' may help in assuring that imported modules are still ' + 'available\n' + ' at the time when the "__del__()" method is called.\n' + '\n' \ + 'object.__repr__(self)\n' + '\n' + ' Called by the "repr()" built-in function to compute the ' + '“official”\n' + ' string representation of an object. If at all possible, ' + 'this\n' + ' should look like a valid Python expression that could be ' + 'used to\n' + ' recreate an object with the same value (given an ' + 'appropriate\n' + ' environment). If this is not possible, a string of the ' + 'form\n' + ' "<...some useful description...>" should be returned. The ' + 'return\n' + ' value must be a string object. If a class defines ' + '"__repr__()" but\n' \ + ' not "__str__()", then "__repr__()" is also used when an ' + '“informal”\n' \ + ' string representation of instances of that class is ' + 'required.\n' \ + '\n' \ + ' This is typically used for debugging, so it is important ' + 'that the\n' \ + ' representation is information-rich and unambiguous. A ' + 'default\n' + ' implementation is provided by the "object" class itself.\n' + '\n' + 'object.__str__(self)\n' + '\n' + ' Called by "str(object)", the default "__format__()" ' + 'implementation,\n' \ + ' and the built-in function "print()", to compute the ' + '“informal” or\n' \ + ' nicely printable string representation of an object. The ' + 'return\n' \ + ' value must be a str object.\n' + '\n' + ' This method differs from "object.__repr__()" in that ' + 'there is no\n' + ' expectation that "__str__()" return a valid Python ' + 'expression: a\n' \ + ' more convenient or concise representation can be used.\n' + '\n' \ + ' The default implementation defined by the built-in type ' + '"object"\n' \ + ' calls "object.__repr__()".\n' + '\n' + 'object.__bytes__(self)\n' \ + '\n' + ' Called by bytes to compute a byte-string representation ' + 'of an\n' \ + ' object. This should return a "bytes" object. The "object" ' + 'class\n' \ + ' itself does not provide this method.\n' \ + '\n' \ + 'object.__format__(self, format_spec)\n' + '\n' \ + ' Called by the "format()" built-in function, and by ' + 'extension,\n' \ + ' evaluation of formatted string literals and the ' + '"str.format()"\n' + ' method, to produce a “formatted” string representation of ' + 'an\n' + ' object. The *format_spec* argument is a string that ' \ + 'contains a\n' + ' description of the formatting options desired. The ' \ + 'interpretation\n' \ + ' of the *format_spec* argument is up to the type ' \ + 'implementing\n' + ' "__format__()", however most classes will either ' \ + 'delegate\n' + ' formatting to one of the built-in types, or use a ' + 'similar\n' \ + ' formatting option syntax.\n' + '\n' + ' See Format Specification Mini-Language for a description ' + 'of the\n' + ' standard formatting syntax.\n' \ + '\n' + ' The return value must be a string object.\n' + '\n' \ + ' The default implementation by the "object" class should ' \ + 'be given an\n' \ + ' empty *format_spec* string. It delegates to "__str__()".\n' \ + '\n' + ' Changed in version 3.4: The __format__ method of "object" ' \ + 'itself\n' \ + ' raises a "TypeError" if passed any non-empty string.\n' + '\n' + ' Changed in version 3.7: "object.__format__(x, \'\')" is ' \ + 'now\n' + ' equivalent to "str(x)" rather than "format(str(x), ' \ + '\'\')".\n' + '\n' + 'object.__lt__(self, other)\n' \ + 'object.__le__(self, other)\n' + 'object.__eq__(self, other)\n' + 'object.__ne__(self, other)\n' \ + 'object.__gt__(self, other)\n' + 'object.__ge__(self, other)\n' + '\n' \ + ' These are the so-called “rich comparison” methods. The\n' + ' correspondence between operator symbols and method names ' + 'is as\n' + ' follows: "xy" calls\n' \ + ' "x.__gt__(y)", and "x>=y" calls "x.__ge__(y)".\n' + '\n' + ' A rich comparison method may return the singleton ' + '"NotImplemented"\n' \ + ' if it does not implement the operation for a given pair ' + 'of\n' + ' arguments. By convention, "False" and "True" are returned ' + 'for a\n' \ + ' successful comparison. However, these methods can return ' + 'any value,\n' + ' so if the comparison operator is used in a Boolean ' + 'context (e.g.,\n' + ' in the condition of an "if" statement), Python will call ' + '"bool()"\n' \ + ' on the value to determine if the result is true or ' \ + 'false.\n' \ + '\n' \ + ' By default, "object" implements "__eq__()" by using "is", ' + 'returning\n' \ + ' "NotImplemented" in the case of a false comparison: "True ' + 'if x is y\n' \ + ' else NotImplemented". For "__ne__()", by default it ' + 'delegates to\n' + ' "__eq__()" and inverts the result unless it is ' + '"NotImplemented".\n' + ' There are no other implied relationships among the ' \ + 'comparison\n' \ + ' operators or default implementations; for example, the ' + 'truth of\n' \ + ' "(x.__hash__".\n' + '\n' + ' If a class that does not override "__eq__()" wishes to ' \ + 'suppress\n' + ' hash support, it should include "__hash__ = None" in the ' + 'class\n' + ' definition. A class which defines its own "__hash__()" ' + 'that\n' + ' explicitly raises a "TypeError" would be incorrectly ' + 'identified as\n' + ' hashable by an "isinstance(obj, ' + 'collections.abc.Hashable)" call.\n' + '\n' + ' Note:\n' \ + '\n' + ' By default, the "__hash__()" values of str and bytes ' + 'objects are\n' \ + ' “salted” with an unpredictable random value. Although ' + 'they\n' + ' remain constant within an individual Python process, ' + 'they are not\n' + ' predictable between repeated invocations of Python.This ' + 'is\n' + ' intended to provide protection against a ' + 'denial-of-service caused\n' + ' by carefully chosen inputs that exploit the worst case\n' + ' performance of a dict insertion, *O*(*n*^2) ' + 'complexity. See\n' + ' http://ocert.org/advisories/ocert-2011-003.html for\n' + ' details.Changing hash values affects the iteration ' + 'order of sets.\n' + ' Python has never made guarantees about this ordering ' + '(and it\n' \ + ' typically varies between 32-bit and 64-bit builds).See ' + 'also\n' + ' "PYTHONHASHSEED".\n' + '\n' + ' Changed in version 3.3: Hash randomization is enabled by ' \ + 'default.\n' + '\n' \ + 'object.__bool__(self)\n' + '\n' \ + ' Called to implement truth value testing and the built-in ' + 'operation\n' + ' "bool()"; should return "False" or "True". When this ' + 'method is not\n' \ + ' defined, "__len__()" is called, if it is defined, and the ' + 'object is\n' \ + ' considered true if its result is nonzero. If a class ' + 'defines\n' + ' neither "__len__()" nor "__bool__()" (which is true of ' + 'the "object"\n' + ' class itself), all its instances are considered true.\n' + '\n' + '\n' + 'Customizing attribute access\n' + '============================\n' + '\n' + 'The following methods can be defined to customize the ' \ + 'meaning of\n' + 'attribute access (use of, assignment to, or deletion of ' + '"x.name") for\n' + 'class instances.\n' + '\n' + 'object.__getattr__(self, name)\n' \ + '\n' + ' Called when the default attribute access fails with an\n' \ + ' "AttributeError" (either "__getattribute__()" raises an\n' + ' "AttributeError" because *name* is not an instance ' + 'attribute or an\n' + ' attribute in the class tree for "self"; or "__get__()" of ' \ + 'a *name*\n' \ + ' property raises "AttributeError"). This method should ' + 'either\n' + ' return the (computed) attribute value or raise an ' + '"AttributeError"\n' + ' exception. The "object" class itself does not provide ' + 'this method.\n' + '\n' + ' Note that if the attribute is found through the normal ' + 'mechanism,\n' + ' "__getattr__()" is not called. (This is an intentional ' + 'asymmetry\n' + ' between "__getattr__()" and "__setattr__()".) This is ' \ + 'done both for\n' \ + ' efficiency reasons and because otherwise "__getattr__()" ' + 'would have\n' \ + ' no way to access other attributes of the instance. Note ' + 'that at\n' + ' least for instance variables, you can fake total control ' \ + 'by not\n' + ' inserting any values in the instance attribute dictionary ' + '(but\n' \ + ' instead inserting them in another object). See the\n' + ' "__getattribute__()" method below for a way to actually ' + 'get total\n' \ + ' control over attribute access.\n' + '\n' + 'object.__getattribute__(self, name)\n' \ + '\n' + ' Called unconditionally to implement attribute accesses ' + 'for\n' + ' instances of the class. If the class also defines ' + '"__getattr__()",\n' + ' the latter will not be called unless "__getattribute__()" ' + 'either\n' \ + ' calls it explicitly or raises an "AttributeError". This ' + 'method\n' + ' should return the (computed) attribute value or raise an\n' + ' "AttributeError" exception. In order to avoid infinite ' + 'recursion in\n' + ' this method, its implementation should always call the ' \ + 'base class\n' + ' method with the same name to access any attributes it ' + 'needs, for\n' \ + ' example, "object.__getattribute__(self, name)".\n' + '\n' + ' Note:\n' \ + '\n' + ' This method may still be bypassed when looking up ' + 'special methods\n' \ + ' as the result of implicit invocation via language ' + 'syntax or\n' + ' built-in functions. See Special method lookup.\n' + '\n' + ' For certain sensitive attribute accesses, raises an ' + 'auditing event\n' + ' "object.__getattr__" with arguments "obj" and "name".\n' + '\n' + 'object.__setattr__(self, name, value)\n' + '\n' + ' Called when an attribute assignment is attempted. This ' + 'is called\n' \ + ' instead of the normal mechanism (i.e. store the value in ' + 'the\n' + ' instance dictionary). *name* is the attribute name, ' + '*value* is the\n' + ' value to be assigned to it.\n' \ + '\n' + ' If "__setattr__()" wants to assign to an instance ' + 'attribute, it\n' \ + ' should call the base class method with the same name, for ' + 'example,\n' + ' "object.__setattr__(self, name, value)".\n' \ + '\n' + ' For certain sensitive attribute assignments, raises an ' + 'auditing\n' \ + ' event "object.__setattr__" with arguments "obj", "name", ' \ + '"value".\n' + '\n' + 'object.__delattr__(self, name)\n' + '\n' + ' Like "__setattr__()" but for attribute deletion instead ' \ + 'of\n' + ' assignment. This should only be implemented if "del ' + 'obj.name" is\n' \ + ' meaningful for the object.\n' + '\n' + ' For certain sensitive attribute deletions, raises an ' \ + 'auditing event\n' + ' "object.__delattr__" with arguments "obj" and "name".\n' + '\n' + 'object.__dir__(self)\n' + '\n' + ' Called when "dir()" is called on the object. An iterable ' + 'must be\n' + ' returned. "dir()" converts the returned iterable to a ' + 'list and\n' + ' sorts it.\n' + '\n' \ + '\n' + 'Customizing module attribute access\n' + '-----------------------------------\n' \ + '\n' + 'Special names "__getattr__" and "__dir__" can be also used ' + 'to\n' + 'customize access to module attributes. The "__getattr__" ' + 'function at\n' \ + 'the module level should accept one argument which is the ' + 'name of an\n' + 'attribute and return the computed value or raise an ' + '"AttributeError".\n' + 'If an attribute is not found on a module object through the ' \ + 'normal\n' + 'lookup, i.e. "object.__getattribute__()", then "__getattr__" ' \ + 'is\n' + 'searched in the module "__dict__" before raising an ' \ + '"AttributeError".\n' + 'If found, it is called with the attribute name and the ' \ + 'result is\n' + 'returned.\n' + '\n' + 'The "__dir__" function should accept no arguments, and ' + 'return an\n' + 'iterable of strings that represents the names accessible on ' \ + 'module. If\n' + 'present, this function overrides the standard "dir()" search ' \ + 'on a\n' + 'module.\n' + '\n' + 'For a more fine grained customization of the module behavior ' \ + '(setting\n' + 'attributes, properties, etc.), one can set the "__class__" ' + 'attribute\n' + 'of a module object to a subclass of "types.ModuleType". For ' + 'example:\n' \ + '\n' + ' import sys\n' \ + ' from types import ModuleType\n' \ + '\n' + ' class VerboseModule(ModuleType):\n' \ + ' def __repr__(self):\n' + " return f'Verbose {self.__name__}'\n" \ + '\n' + ' def __setattr__(self, attr, value):\n' + " print(f'Setting {attr}...')\n" + ' super().__setattr__(attr, value)\n' \ + '\n' + ' sys.modules[__name__].__class__ = VerboseModule\n' \ + '\n' + 'Note:\n' + '\n' + ' Defining module "__getattr__" and setting module ' + '"__class__" only\n' + ' affect lookups made using the attribute access syntax – ' + 'directly\n' + ' accessing the module globals (whether by code within the ' + 'module, or\n' + ' via a reference to the module’s globals dictionary) is ' \ + 'unaffected.\n' + '\n' + 'Changed in version 3.5: "__class__" module attribute is now ' \ + 'writable.\n' + '\n' \ + 'Added in version 3.7: "__getattr__" and "__dir__" module ' + 'attributes.\n' + '\n' + 'See also:\n' + '\n' + ' **PEP 562** - Module __getattr__ and __dir__\n' + ' Describes the "__getattr__" and "__dir__" functions on ' + 'modules.\n' + '\n' \ + '\n' + 'Implementing Descriptors\n' + '------------------------\n' \ + '\n' + 'The following methods only apply when an instance of the ' + 'class\n' + 'containing the method (a so-called *descriptor* class) ' + 'appears in an\n' + '*owner* class (the descriptor must be in either the owner’s ' + 'class\n' + 'dictionary or in the class dictionary for one of its ' + 'parents). In the\n' + 'examples below, “the attribute” refers to the attribute ' + 'whose name is\n' + 'the key of the property in the owner class’ "__dict__". The ' + '"object"\n' + 'class itself does not implement any of these protocols.\n' + '\n' + 'object.__get__(self, instance, owner=None)\n' + '\n' + ' Called to get the attribute of the owner class (class ' \ + 'attribute\n' + ' access) or of an instance of that class (instance ' + 'attribute\n' + ' access). The optional *owner* argument is the owner ' \ + 'class, while\n' \ + ' *instance* is the instance that the attribute was ' + 'accessed through,\n' + ' or "None" when the attribute is accessed through the ' + '*owner*.\n' + '\n' \ + ' This method should return the computed attribute value or ' + 'raise an\n' \ + ' "AttributeError" exception.\n' + '\n' + ' **PEP 252** specifies that "__get__()" is callable with ' + 'one or two\n' \ + ' arguments. Python’s own built-in descriptors support ' + 'this\n' + ' specification; however, it is likely that some ' \ + 'third-party tools\n' + ' have descriptors that require both arguments. Python’s ' \ + 'own\n' + ' "__getattribute__()" implementation always passes in both ' + 'arguments\n' + ' whether they are required or not.\n' + '\n' + 'object.__set__(self, instance, value)\n' + '\n' \ + ' Called to set the attribute on an instance *instance* of ' + 'the owner\n' \ + ' class to a new value, *value*.\n' + '\n' + ' Note, adding "__set__()" or "__delete__()" changes the ' + 'kind of\n' + ' descriptor to a “data descriptor”. See Invoking ' + 'Descriptors for\n' + ' more details.\n' \ + '\n' + 'object.__delete__(self, instance)\n' + '\n' + ' Called to delete the attribute on an instance *instance* ' + 'of the\n' \ + ' owner class.\n' + '\n' + 'Instances of descriptors may also have the "__objclass__" ' + 'attribute\n' \ + 'present:\n' \ + '\n' + 'object.__objclass__\n' + '\n' + ' The attribute "__objclass__" is interpreted by the ' + '"inspect" module\n' + ' as specifying the class where this object was defined ' + '(setting this\n' + ' appropriately can assist in runtime introspection of ' + 'dynamic class\n' + ' attributes). For callables, it may indicate that an ' + 'instance of the\n' + ' given type (or a subclass) is expected or required as the ' + 'first\n' + ' positional argument (for example, CPython sets this ' + 'attribute for\n' + ' unbound methods that are implemented in C).\n' + '\n' \ + '\n' \ + 'Invoking Descriptors\n' + '--------------------\n' + '\n' + 'In general, a descriptor is an object attribute with ' + '“binding\n' \ + 'behavior”, one whose attribute access has been overridden by ' + 'methods\n' \ + 'in the descriptor protocol: "__get__()", "__set__()", and\n' + '"__delete__()". If any of those methods are defined for an ' + 'object, it\n' + 'is said to be a descriptor.\n' \ + '\n' + 'The default behavior for attribute access is to get, set, or ' + 'delete\n' + 'the attribute from an object’s dictionary. For instance, ' \ + '"a.x" has a\n' + 'lookup chain starting with "a.__dict__[\'x\']", then\n' \ + '"type(a).__dict__[\'x\']", and continuing through the base ' \ + 'classes of\n' \ + '"type(a)" excluding metaclasses.\n' + '\n' \ + 'However, if the looked-up value is an object defining one of ' + 'the\n' + 'descriptor methods, then Python may override the default ' + 'behavior and\n' \ + 'invoke the descriptor method instead. Where this occurs in ' + 'the\n' + 'precedence chain depends on which descriptor methods were ' + 'defined and\n' + 'how they were called.\n' + '\n' + 'The starting point for descriptor invocation is a binding, ' \ + '"a.x". How\n' + 'the arguments are assembled depends on "a":\n' + '\n' \ + 'Direct Call\n' + ' The simplest and least common call is when user code ' + 'directly\n' + ' invokes a descriptor method: "x.__get__(a)".\n' + '\n' + 'Instance Binding\n' + ' If binding to an object instance, "a.x" is transformed ' + 'into the\n' \ + ' call: "type(a).__dict__[\'x\'].__get__(a, type(a))".\n' + '\n' + 'Class Binding\n' + ' If binding to a class, "A.x" is transformed into the ' + 'call:\n' \ + ' "A.__dict__[\'x\'].__get__(None, A)".\n' + '\n' \ + 'Super Binding\n' + ' A dotted lookup such as "super(A, a).x" searches\n' + ' "a.__class__.__mro__" for a base class "B" following "A" ' + 'and then\n' + ' returns "B.__dict__[\'x\'].__get__(a, A)". If not a ' + 'descriptor, "x"\n' + ' is returned unchanged.\n' + '\n' + 'For instance bindings, the precedence of descriptor ' + 'invocation depends\n' + 'on which descriptor methods are defined. A descriptor can ' + 'define any\n' \ + 'combination of "__get__()", "__set__()" and "__delete__()". ' + 'If it\n' + 'does not define "__get__()", then accessing the attribute ' + 'will return\n' + 'the descriptor object itself unless there is a value in the ' \ + 'object’s\n' + 'instance dictionary. If the descriptor defines "__set__()" ' + 'and/or\n' \ + '"__delete__()", it is a data descriptor; if it defines ' + 'neither, it is\n' + 'a non-data descriptor. Normally, data descriptors define ' + 'both\n' + '"__get__()" and "__set__()", while non-data descriptors have ' + 'just the\n' + '"__get__()" method. Data descriptors with "__get__()" and ' + '"__set__()"\n' + '(and/or "__delete__()") defined always override a ' + 'redefinition in an\n' + 'instance dictionary. In contrast, non-data descriptors can ' + 'be\n' \ + 'overridden by instances.\n' + '\n' + 'Python methods (including those decorated with ' + '"@staticmethod" and\n' + '"@classmethod") are implemented as non-data descriptors. ' + 'Accordingly,\n' + 'instances can redefine and override methods. This allows ' + 'individual\n' + 'instances to acquire behaviors that differ from other ' \ + 'instances of the\n' + 'same class.\n' + '\n' + 'The "property()" function is implemented as a data ' + 'descriptor.\n' + 'Accordingly, instances cannot override the behavior of a ' + 'property.\n' + '\n' + '\n' + '__slots__\n' + '---------\n' + '\n' + '*__slots__* allow us to explicitly declare data members ' + '(like\n' + 'properties) and deny the creation of "__dict__" and ' + '*__weakref__*\n' + '(unless explicitly declared in *__slots__* or available in a ' \ + 'parent.)\n' + '\n' + 'The space saved over using "__dict__" can be significant. ' \ + 'Attribute\n' + 'lookup speed can be significantly improved as well.\n' + '\n' + 'object.__slots__\n' \ + '\n' + ' This class variable can be assigned a string, iterable, ' + 'or sequence\n' + ' of strings with variable names used by instances. ' + '*__slots__*\n' + ' reserves space for the declared variables and prevents ' + 'the\n' + ' automatic creation of "__dict__" and *__weakref__* for ' + 'each\n' + ' instance.\n' + '\n' + 'Notes on using *__slots__*:\n' + '\n' \ + '* When inheriting from a class without *__slots__*, the ' + '"__dict__" and\n' + ' *__weakref__* attribute of the instances will always be ' + 'accessible.\n' + '\n' + '* Without a "__dict__" variable, instances cannot be ' \ + 'assigned new\n' + ' variables not listed in the *__slots__* definition. ' \ + 'Attempts to\n' + ' assign to an unlisted variable name raises ' + '"AttributeError". If\n' + ' dynamic assignment of new variables is desired, then add\n' + ' "\'__dict__\'" to the sequence of strings in the ' \ + '*__slots__*\n' + ' declaration.\n' + '\n' + '* Without a *__weakref__* variable for each instance, ' \ + 'classes defining\n' + ' *__slots__* do not support "weak references" to its ' + 'instances. If\n' + ' weak reference support is needed, then add ' + '"\'__weakref__\'" to the\n' + ' sequence of strings in the *__slots__* declaration.\n' + '\n' + '* *__slots__* are implemented at the class level by ' + 'creating\n' + ' descriptors for each variable name. As a result, class ' + 'attributes\n' \ + ' cannot be used to set default values for instance ' + 'variables defined\n' + ' by *__slots__*; otherwise, the class attribute would ' + 'overwrite the\n' + ' descriptor assignment.\n' + '\n' \ + '* The action of a *__slots__* declaration is not limited to ' + 'the class\n' + ' where it is defined. *__slots__* declared in parents are ' + 'available\n' + ' in child classes. However, instances of a child subclass ' + 'will get a\n' + ' "__dict__" and *__weakref__* unless the subclass also ' + 'defines\n' \ + ' *__slots__* (which should only contain names of any ' + '*additional*\n' + ' slots).\n' + '\n' + '* If a class defines a slot also defined in a base class, ' + 'the instance\n' + ' variable defined by the base class slot is inaccessible ' + '(except by\n' + ' retrieving its descriptor directly from the base class). ' + 'This\n' + ' renders the meaning of the program undefined. In the ' \ + 'future, a\n' + ' check may be added to prevent this.\n' + '\n' + '* "TypeError" will be raised if nonempty *__slots__* are ' + 'defined for a\n' + ' class derived from a ""variable-length" built-in type" ' \ + 'such as\n' + ' "int", "bytes", and "tuple".\n' + '\n' + '* Any non-string *iterable* may be assigned to *__slots__*.\n' + '\n' + '* If a "dictionary" is used to assign *__slots__*, the ' \ + 'dictionary keys\n' + ' will be used as the slot names. The values of the ' + 'dictionary can be\n' + ' used to provide per-attribute docstrings that will be ' + 'recognised by\n' + ' "inspect.getdoc()" and displayed in the output of ' + '"help()".\n' + '\n' + '* "__class__" assignment works only if both classes have the ' + 'same\n' + ' *__slots__*.\n' + '\n' + '* Multiple inheritance with multiple slotted parent classes ' + 'can be\n' + ' used, but only one parent is allowed to have attributes ' \ + 'created by\n' + ' slots (the other bases must have empty slot layouts) - ' + 'violations\n' + ' raise "TypeError".\n' + '\n' \ + '* If an *iterator* is used for *__slots__* then a ' + '*descriptor* is\n' + ' created for each of the iterator’s values. However, the ' + '*__slots__*\n' + ' attribute will be an empty iterator.\n' \ + '\n' + '\n' + 'Customizing class creation\n' + '==========================\n' \ + '\n' + 'Whenever a class inherits from another class, ' + '"__init_subclass__()" is\n' \ + 'called on the parent class. This way, it is possible to ' + 'write classes\n' + 'which change the behavior of subclasses. This is closely ' + 'related to\n' + 'class decorators, but where class decorators only affect the ' + 'specific\n' + 'class they’re applied to, "__init_subclass__" solely applies ' + 'to future\n' + 'subclasses of the class defining the method.\n' + '\n' \ + 'classmethod object.__init_subclass__(cls)\n' + '\n' + ' This method is called whenever the containing class is ' \ + 'subclassed.\n' + ' *cls* is then the new subclass. If defined as a normal ' + 'instance\n' \ + ' method, this method is implicitly converted to a class ' + 'method.\n' + '\n' \ + ' Keyword arguments which are given to a new class are ' + 'passed to the\n' + ' parent class’s "__init_subclass__". For compatibility ' \ + 'with other\n' \ + ' classes using "__init_subclass__", one should take out ' + 'the needed\n' + ' keyword arguments and pass the others over to the base ' + 'class, as\n' + ' in:\n' + '\n' \ + ' class Philosopher:\n' + ' def __init_subclass__(cls, /, default_name, ' + '**kwargs):\n' + ' super().__init_subclass__(**kwargs)\n' + ' cls.default_name = default_name\n' + '\n' + ' class AustralianPhilosopher(Philosopher, ' + 'default_name="Bruce"):\n' + ' pass\n' + '\n' + ' The default implementation "object.__init_subclass__" ' + 'does nothing,\n' + ' but raises an error if it is called with any arguments.\n' \ + '\n' + ' Note:\n' + '\n' + ' The metaclass hint "metaclass" is consumed by the rest ' + 'of the\n' + ' type machinery, and is never passed to ' + '"__init_subclass__"\n' + ' implementations. The actual metaclass (rather than the ' + 'explicit\n' \ + ' hint) can be accessed as "type(cls)".\n' \ + '\n' + ' Added in version 3.6.\n' + '\n' + 'When a class is created, "type.__new__()" scans the class ' \ + 'variables\n' + 'and makes callbacks to those with a "__set_name__()" hook.\n' + '\n' \ + 'object.__set_name__(self, owner, name)\n' \ + '\n' \ + ' Automatically called at the time the owning class *owner* ' + 'is\n' + ' created. The object has been assigned to *name* in that ' + 'class:\n' + '\n' + ' class A:\n' + ' x = C() # Automatically calls: x.__set_name__(A, ' + "'x')\n" + '\n' + ' If the class variable is assigned after the class is ' + 'created,\n' + ' "__set_name__()" will not be called automatically. If ' + 'needed,\n' + ' "__set_name__()" can be called directly:\n' + '\n' + ' class A:\n' \ + ' pass\n' + '\n' + ' c = C()\n' + ' A.x = c # The hook is not called\n' + " c.__set_name__(A, 'x') # Manually invoke the hook\n" + '\n' \ + ' See Creating the class object for more details.\n' + '\n' + ' Added in version 3.6.\n' \ + '\n' + '\n' + 'Metaclasses\n' + '-----------\n' + '\n' + 'By default, classes are constructed using "type()". The ' + 'class body is\n' + 'executed in a new namespace and the class name is bound ' + 'locally to the\n' + 'result of "type(name, bases, namespace)".\n' + '\n' + 'The class creation process can be customized by passing the\n' + '"metaclass" keyword argument in the class definition line, ' \ + 'or by\n' + 'inheriting from an existing class that included such an ' \ + 'argument. In\n' + 'the following example, both "MyClass" and "MySubclass" are ' + 'instances\n' + 'of "Meta":\n' \ + '\n' + ' class Meta(type):\n' + ' pass\n' + '\n' \ + ' class MyClass(metaclass=Meta):\n' + ' pass\n' \ + '\n' + ' class MySubclass(MyClass):\n' + ' pass\n' \ + '\n' + 'Any other keyword arguments that are specified in the class ' + 'definition\n' + 'are passed through to all metaclass operations described ' + 'below.\n' + '\n' + 'When a class definition is executed, the following steps ' + 'occur:\n' + '\n' \ + '* MRO entries are resolved;\n' + '\n' + '* the appropriate metaclass is determined;\n' \ + '\n' \ + '* the class namespace is prepared;\n' + '\n' + '* the class body is executed;\n' + '\n' + '* the class object is created.\n' + '\n' \ + '\n' + 'Resolving MRO entries\n' + '---------------------\n' + '\n' + 'object.__mro_entries__(self, bases)\n' + '\n' \ + ' If a base that appears in a class definition is not an ' + 'instance of\n' \ + ' "type", then an "__mro_entries__()" method is searched on ' + 'the base.\n' \ + ' If an "__mro_entries__()" method is found, the base is ' + 'substituted\n' \ + ' with the result of a call to "__mro_entries__()" when ' + 'creating the\n' + ' class. The method is called with the original bases tuple ' + 'passed to\n' + ' the *bases* parameter, and must return a tuple of classes ' \ + 'that will\n' + ' be used instead of the base. The returned tuple may be ' + 'empty: in\n' + ' these cases, the original base is ignored.\n' \ + '\n' + 'See also:\n' + '\n' + ' "types.resolve_bases()"\n' \ + ' Dynamically resolve bases that are not instances of ' \ + '"type".\n' + '\n' + ' "types.get_original_bases()"\n' \ + ' Retrieve a class’s “original bases” prior to ' + 'modifications by\n' + ' "__mro_entries__()".\n' + '\n' + ' **PEP 560**\n' + ' Core support for typing module and generic types.\n' + '\n' + '\n' + 'Determining the appropriate metaclass\n' \ + '-------------------------------------\n' + '\n' \ + 'The appropriate metaclass for a class definition is ' + 'determined as\n' + 'follows:\n' + '\n' + '* if no bases and no explicit metaclass are given, then ' + '"type()" is\n' + ' used;\n' + '\n' + '* if an explicit metaclass is given and it is *not* an ' \ + 'instance of\n' + ' "type()", then it is used directly as the metaclass;\n' + '\n' + '* if an instance of "type()" is given as the explicit ' \ + 'metaclass, or\n' + ' bases are defined, then the most derived metaclass is ' + 'used.\n' \ + '\n' \ + 'The most derived metaclass is selected from the explicitly ' + 'specified\n' \ + 'metaclass (if any) and the metaclasses (i.e. "type(cls)") of ' + 'all\n' + 'specified base classes. The most derived metaclass is one ' + 'which is a\n' + 'subtype of *all* of these candidate metaclasses. If none of ' + 'the\n' + 'candidate metaclasses meets that criterion, then the class ' + 'definition\n' \ + 'will fail with "TypeError".\n' + '\n' + '\n' + 'Preparing the class namespace\n' \ + '-----------------------------\n' + '\n' + 'Once the appropriate metaclass has been identified, then the ' + 'class\n' + 'namespace is prepared. If the metaclass has a "__prepare__" ' + 'attribute,\n' + 'it is called as "namespace = metaclass.__prepare__(name, ' + 'bases,\n' + '**kwds)" (where the additional keyword arguments, if any, ' + 'come from\n' + 'the class definition). The "__prepare__" method should be ' + 'implemented\n' + 'as a "classmethod". The namespace returned by "__prepare__" ' + 'is passed\n' + 'in to "__new__", but when the final class object is created ' + 'the\n' \ + 'namespace is copied into a new "dict".\n' \ + '\n' + 'If the metaclass has no "__prepare__" attribute, then the ' \ + 'class\n' + 'namespace is initialised as an empty ordered mapping.\n' + '\n' \ + 'See also:\n' + '\n' \ + ' **PEP 3115** - Metaclasses in Python 3000\n' \ + ' Introduced the "__prepare__" namespace hook\n' + '\n' \ + '\n' + 'Executing the class body\n' \ + '------------------------\n' + '\n' + 'The class body is executed (approximately) as "exec(body, ' + 'globals(),\n' + 'namespace)". The key difference from a normal call to ' + '"exec()" is that\n' \ + 'lexical scoping allows the class body (including any ' \ + 'methods) to\n' + 'reference names from the current and outer scopes when the ' + 'class\n' + 'definition occurs inside a function.\n' + '\n' + 'However, even when the class definition occurs inside the ' + 'function,\n' \ + 'methods defined inside the class still cannot see names ' + 'defined at the\n' \ + 'class scope. Class variables must be accessed through the ' \ + 'first\n' + 'parameter of instance or class methods, or through the ' \ + 'implicit\n' + 'lexically scoped "__class__" reference described in the next ' + 'section.\n' + '\n' \ + '\n' + 'Creating the class object\n' + '-------------------------\n' + '\n' + 'Once the class namespace has been populated by executing the ' + 'class\n' \ + 'body, the class object is created by calling ' \ + '"metaclass(name, bases,\n' + 'namespace, **kwds)" (the additional keywords passed here are ' + 'the same\n' \ + 'as those passed to "__prepare__").\n' + '\n' + 'This class object is the one that will be referenced by the ' + 'zero-\n' + 'argument form of "super()". "__class__" is an implicit ' + 'closure\n' \ + 'reference created by the compiler if any methods in a class ' + 'body refer\n' \ + 'to either "__class__" or "super". This allows the zero ' \ + 'argument form\n' \ + 'of "super()" to correctly identify the class being defined ' \ + 'based on\n' + 'lexical scoping, while the class or instance that was used ' + 'to make the\n' + 'current call is identified based on the first argument ' + 'passed to the\n' \ + 'method.\n' + '\n' + '**CPython implementation detail:** In CPython 3.6 and later, ' + 'the\n' + '"__class__" cell is passed to the metaclass as a ' + '"__classcell__" entry\n' + 'in the class namespace. If present, this must be propagated ' \ + 'up to the\n' + '"type.__new__" call in order for the class to be ' + 'initialised\n' + 'correctly. Failing to do so will result in a "RuntimeError" ' + 'in Python\n' \ + '3.8.\n' \ + '\n' + 'When using the default metaclass "type", or any metaclass ' + 'that\n' + 'ultimately calls "type.__new__", the following additional\n' \ + 'customization steps are invoked after creating the class ' \ + 'object:\n' + '\n' + '1. The "type.__new__" method collects all of the attributes ' \ + 'in the\n' + ' class namespace that define a "__set_name__()" method;\n' \ + '\n' + '2. Those "__set_name__" methods are called with the class ' \ + 'being\n' + ' defined and the assigned name of that particular ' + 'attribute;\n' + '\n' + '3. The "__init_subclass__()" hook is called on the immediate ' + 'parent of\n' + ' the new class in its method resolution order.\n' \ + '\n' \ + 'After the class object is created, it is passed to the ' + 'class\n' + 'decorators included in the class definition (if any) and the ' + 'resulting\n' + 'object is bound in the local namespace as the defined ' + 'class.\n' \ + '\n' + 'When a new class is created by "type.__new__", the object ' + 'provided as\n' + 'the namespace parameter is copied to a new ordered mapping ' + 'and the\n' + 'original object is discarded. The new copy is wrapped in a ' + 'read-only\n' + 'proxy, which becomes the "__dict__" attribute of the class ' + 'object.\n' + '\n' \ + 'See also:\n' + '\n' + ' **PEP 3135** - New super\n' + ' Describes the implicit "__class__" closure reference\n' + '\n' + '\n' \ + 'Uses for metaclasses\n' + '--------------------\n' \ + '\n' + 'The potential uses for metaclasses are boundless. Some ideas ' + 'that have\n' \ + 'been explored include enum, logging, interface checking, ' \ + 'automatic\n' + 'delegation, automatic property creation, proxies, ' \ + 'frameworks, and\n' \ + 'automatic resource locking/synchronization.\n' + '\n' + '\n' + 'Customizing instance and subclass checks\n' + '========================================\n' + '\n' + 'The following methods are used to override the default ' + 'behavior of the\n' + '"isinstance()" and "issubclass()" built-in functions.\n' + '\n' + 'In particular, the metaclass "abc.ABCMeta" implements these ' + 'methods in\n' + 'order to allow the addition of Abstract Base Classes (ABCs) ' \ + 'as\n' + '“virtual base classes” to any class or type (including ' + 'built-in\n' \ + 'types), including other ABCs.\n' + '\n' + 'type.__instancecheck__(self, instance)\n' \ + '\n' + ' Return true if *instance* should be considered a (direct ' + 'or\n' \ + ' indirect) instance of *class*. If defined, called to ' + 'implement\n' + ' "isinstance(instance, class)".\n' + '\n' + 'type.__subclasscheck__(self, subclass)\n' + '\n' \ + ' Return true if *subclass* should be considered a (direct ' + 'or\n' + ' indirect) subclass of *class*. If defined, called to ' + 'implement\n' + ' "issubclass(subclass, class)".\n' + '\n' + 'Note that these methods are looked up on the type ' + '(metaclass) of a\n' + 'class. They cannot be defined as class methods in the ' + 'actual class.\n' \ + 'This is consistent with the lookup of special methods that ' + 'are called\n' + 'on instances, only in this case the instance is itself a ' + 'class.\n' + '\n' + 'See also:\n' + '\n' + ' **PEP 3119** - Introducing Abstract Base Classes\n' + ' Includes the specification for customizing ' + '"isinstance()" and\n' + ' "issubclass()" behavior through "__instancecheck__()" ' + 'and\n' + ' "__subclasscheck__()", with motivation for this ' \ + 'functionality in\n' + ' the context of adding Abstract Base Classes (see the ' \ + '"abc"\n' + ' module) to the language.\n' + '\n' + '\n' + 'Emulating generic types\n' + '=======================\n' + '\n' + 'When using *type annotations*, it is often useful to ' + '*parameterize* a\n' + '*generic type* using Python’s square-brackets notation. For ' + 'example,\n' + 'the annotation "list[int]" might be used to signify a "list" ' + 'in which\n' + 'all the elements are of type "int".\n' + '\n' \ + 'See also:\n' + '\n' + ' **PEP 484** - Type Hints\n' + ' Introducing Python’s framework for type annotations\n' + '\n' + ' Generic Alias Types\n' + ' Documentation for objects representing parameterized ' + 'generic\n' + ' classes\n' \ + '\n' + ' Generics, user-defined generics and "typing.Generic"\n' + ' Documentation on how to implement generic classes that ' + 'can be\n' + ' parameterized at runtime and understood by static ' + 'type-checkers.\n' + '\n' \ + 'A class can *generally* only be parameterized if it defines ' + 'the\n' + 'special class method "__class_getitem__()".\n' \ + '\n' + 'classmethod object.__class_getitem__(cls, key)\n' + '\n' + ' Return an object representing the specialization of a ' + 'generic class\n' + ' by type arguments found in *key*.\n' + '\n' + ' When defined on a class, "__class_getitem__()" is ' + 'automatically a\n' + ' class method. As such, there is no need for it to be ' + 'decorated with\n' + ' "@classmethod" when it is defined.\n' + '\n' + '\n' + 'The purpose of *__class_getitem__*\n' \ + '----------------------------------\n' + '\n' + 'The purpose of "__class_getitem__()" is to allow runtime\n' + 'parameterization of standard-library generic classes in ' + 'order to more\n' + 'easily apply *type hints* to these classes.\n' + '\n' + 'To implement custom generic classes that can be ' + 'parameterized at\n' + 'runtime and understood by static type-checkers, users should ' + 'either\n' + 'inherit from a standard library class that already ' + 'implements\n' + '"__class_getitem__()", or inherit from "typing.Generic", ' + 'which has its\n' + 'own implementation of "__class_getitem__()".\n' + '\n' + 'Custom implementations of "__class_getitem__()" on classes ' + 'defined\n' + 'outside of the standard library may not be understood by ' + 'third-party\n' + 'type-checkers such as mypy. Using "__class_getitem__()" on ' + 'any class\n' + 'for purposes other than type hinting is discouraged.\n' + '\n' \ + '\n' + '*__class_getitem__* versus *__getitem__*\n' \ + '----------------------------------------\n' + '\n' \ + 'Usually, the subscription of an object using square brackets ' + 'will call\n' + 'the "__getitem__()" instance method defined on the object’s ' \ + 'class.\n' + 'However, if the object being subscribed is itself a class, ' + 'the class\n' + 'method "__class_getitem__()" may be called instead.\n' \ + '"__class_getitem__()" should return a GenericAlias object if ' + 'it is\n' + 'properly defined.\n' + '\n' + 'Presented with the *expression* "obj[x]", the Python ' + 'interpreter\n' + 'follows something like the following process to decide ' \ + 'whether\n' + '"__getitem__()" or "__class_getitem__()" should be called:\n' + '\n' \ + ' from inspect import isclass\n' + '\n' + ' def subscribe(obj, x):\n' + ' """Return the result of the expression \'obj[x]\'"""\n' + '\n' + ' class_of_obj = type(obj)\n' + '\n' + ' # If the class of obj defines __getitem__,\n' + ' # call class_of_obj.__getitem__(obj, x)\n' + " if hasattr(class_of_obj, '__getitem__'):\n" + ' return class_of_obj.__getitem__(obj, x)\n' + '\n' + ' # Else, if obj is a class and defines ' + '__class_getitem__,\n' + ' # call obj.__class_getitem__(x)\n' + ' elif isclass(obj) and hasattr(obj, ' + "'__class_getitem__'):\n" + ' return obj.__class_getitem__(x)\n' + '\n' + ' # Else, raise an exception\n' \ + ' else:\n' + ' raise TypeError(\n' + ' f"\'{class_of_obj.__name__}\' object is not ' + 'subscriptable"\n' + ' )\n' + '\n' \ + 'In Python, all classes are themselves instances of other ' + 'classes. The\n' + 'class of a class is known as that class’s *metaclass*, and ' + 'most\n' + 'classes have the "type" class as their metaclass. "type" ' + 'does not\n' + 'define "__getitem__()", meaning that expressions such as ' + '"list[int]",\n' + '"dict[str, float]" and "tuple[str, bytes]" all result in\n' + '"__class_getitem__()" being called:\n' \ + '\n' + ' >>> # list has class "type" as its metaclass, like most ' \ + 'classes:\n' + ' >>> type(list)\n' + " \n" + ' >>> type(dict) == type(list) == type(tuple) == type(str) ' + '== type(bytes)\n' + ' True\n' + ' >>> # "list[int]" calls "list.__class_getitem__(int)"\n' + ' >>> list[int]\n' + ' list[int]\n' \ + ' >>> # list.__class_getitem__ returns a GenericAlias ' + 'object:\n' + ' >>> type(list[int])\n' + " \n" + '\n' + 'However, if a class has a custom metaclass that defines\n' + '"__getitem__()", subscribing the class may result in ' + 'different\n' + 'behaviour. An example of this can be found in the "enum" ' + 'module:\n' + '\n' + ' >>> from enum import Enum\n' \ + ' >>> class Menu(Enum):\n' + ' ... """A breakfast menu"""\n' + " ... SPAM = 'spam'\n" + " ... BACON = 'bacon'\n" + ' ...\n' + ' >>> # Enum classes have a custom metaclass:\n' + ' >>> type(Menu)\n' + " \n" + ' >>> # EnumMeta defines __getitem__,\n' + ' >>> # so __class_getitem__ is not called,\n' + ' >>> # and the result is not a GenericAlias object:\n' + " >>> Menu['SPAM']\n" \ + " \n" \ + " >>> type(Menu['SPAM'])\n" + " \n" + '\n' + 'See also:\n' + '\n' + ' **PEP 560** - Core Support for typing module and generic ' \ + 'types\n' + ' Introducing "__class_getitem__()", and outlining when ' + 'a\n' + ' subscription results in "__class_getitem__()" being ' \ + 'called\n' + ' instead of "__getitem__()"\n' + '\n' + '\n' + 'Emulating callable objects\n' + '==========================\n' + '\n' + 'object.__call__(self[, args...])\n' + '\n' + ' Called when the instance is “called” as a function; if ' \ + 'this method\n' + ' is defined, "x(arg1, arg2, ...)" roughly translates to\n' + ' "type(x).__call__(x, arg1, ...)". The "object" class ' + 'itself does\n' + ' not provide this method.\n' + '\n' + '\n' + 'Emulating container types\n' + '=========================\n' + '\n' + 'The following methods can be defined to implement container ' \ + 'objects.\n' + 'None of them are provided by the "object" class itself. ' + 'Containers\n' + 'usually are *sequences* (such as "lists" or "tuples") or ' + '*mappings*\n' + '(like *dictionaries*), but can represent other containers as ' + 'well.\n' + 'The first set of methods is used either to emulate a ' + 'sequence or to\n' + 'emulate a mapping; the difference is that for a sequence, ' + 'the\n' + 'allowable keys should be the integers *k* for which "0 <= k ' \ + '< N" where\n' + '*N* is the length of the sequence, or "slice" objects, which ' + 'define a\n' + 'range of items. It is also recommended that mappings ' + 'provide the\n' + 'methods "keys()", "values()", "items()", "get()", ' + '"clear()",\n' + '"setdefault()", "pop()", "popitem()", "copy()", and ' + '"update()"\n' + 'behaving similar to those for Python’s standard "dictionary" ' + 'objects.\n' + 'The "collections.abc" module provides a "MutableMapping" ' \ + '*abstract\n' + 'base class* to help create those methods from a base set of\n' + '"__getitem__()", "__setitem__()", "__delitem__()", and ' + '"keys()".\n' \ + 'Mutable sequences should provide methods "append()", ' + '"count()",\n' + '"index()", "extend()", "insert()", "pop()", "remove()", ' + '"reverse()"\n' + 'and "sort()", like Python standard "list" objects. Finally, ' + 'sequence\n' \ + 'types should implement addition (meaning concatenation) and\n' + 'multiplication (meaning repetition) by defining the methods\n' \ + '"__add__()", "__radd__()", "__iadd__()", "__mul__()", ' + '"__rmul__()" and\n' + '"__imul__()" described below; they should not define other ' + 'numerical\n' + 'operators. It is recommended that both mappings and ' + 'sequences\n' \ + 'implement the "__contains__()" method to allow efficient use ' \ + 'of the\n' \ + '"in" operator; for mappings, "in" should search the ' + 'mapping’s keys;\n' + 'for sequences, it should search through the values. It is ' + 'further\n' + 'recommended that both mappings and sequences implement the\n' + '"__iter__()" method to allow efficient iteration through ' + 'the\n' + 'container; for mappings, "__iter__()" should iterate through ' + 'the\n' \ + 'object’s keys; for sequences, it should iterate through the ' + 'values.\n' + '\n' + 'object.__len__(self)\n' + '\n' + ' Called to implement the built-in function "len()". ' \ + 'Should return\n' + ' the length of the object, an integer ">=" 0. Also, an ' + 'object that\n' + ' doesn’t define a "__bool__()" method and whose ' + '"__len__()" method\n' + ' returns zero is considered to be false in a Boolean ' + 'context.\n' + '\n' + ' **CPython implementation detail:** In CPython, the length ' \ + 'is\n' + ' required to be at most "sys.maxsize". If the length is ' + 'larger than\n' + ' "sys.maxsize" some features (such as "len()") may raise\n' + ' "OverflowError". To prevent raising "OverflowError" by ' + 'truth value\n' + ' testing, an object must define a "__bool__()" method.\n' + '\n' \ + 'object.__length_hint__(self)\n' + '\n' + ' Called to implement "operator.length_hint()". Should ' + 'return an\n' \ + ' estimated length for the object (which may be greater or ' \ + 'less than\n' + ' the actual length). The length must be an integer ">=" 0. ' \ + 'The\n' + ' return value may also be "NotImplemented", which is ' + 'treated the\n' + ' same as if the "__length_hint__" method didn’t exist at ' + 'all. This\n' + ' method is purely an optimization and is never required ' \ + 'for\n' + ' correctness.\n' + '\n' + ' Added in version 3.4.\n' + '\n' + 'Note:\n' + '\n' + ' Slicing is done exclusively with the following three ' + 'methods. A\n' + ' call like\n' + '\n' + ' a[1:2] = b\n' + '\n' + ' is translated to\n' + '\n' + ' a[slice(1, 2, None)] = b\n' + '\n' \ + ' and so forth. Missing slice items are always filled in ' + 'with "None".\n' + '\n' + 'object.__getitem__(self, key)\n' + '\n' + ' Called to implement evaluation of "self[key]". For ' + '*sequence*\n' + ' types, the accepted keys should be integers. Optionally, ' \ + 'they may\n' + ' support "slice" objects as well. Negative index support ' \ + 'is also\n' + ' optional. If *key* is of an inappropriate type, ' + '"TypeError" may be\n' + ' raised; if *key* is a value outside the set of indexes ' + 'for the\n' \ + ' sequence (after any special interpretation of negative ' + 'values),\n' \ + ' "IndexError" should be raised. For *mapping* types, if ' + '*key* is\n' + ' missing (not in the container), "KeyError" should be ' + 'raised.\n' + '\n' + ' Note:\n' + '\n' + ' "for" loops expect that an "IndexError" will be raised ' \ + 'for\n' + ' illegal indexes to allow proper detection of the end of ' \ + 'the\n' + ' sequence.\n' + '\n' \ + ' Note:\n' + '\n' + ' When subscripting a *class*, the special class method\n' \ + ' "__class_getitem__()" may be called instead of ' + '"__getitem__()".\n' + ' See __class_getitem__ versus __getitem__ for more ' \ + 'details.\n' \ + '\n' + 'object.__setitem__(self, key, value)\n' \ + '\n' + ' Called to implement assignment to "self[key]". Same note ' + 'as for\n' \ + ' "__getitem__()". This should only be implemented for ' \ + 'mappings if\n' + ' the objects support changes to the values for keys, or if ' + 'new keys\n' + ' can be added, or for sequences if elements can be ' \ + 'replaced. The\n' + ' same exceptions should be raised for improper *key* ' + 'values as for\n' + ' the "__getitem__()" method.\n' + '\n' \ + 'object.__delitem__(self, key)\n' + '\n' + ' Called to implement deletion of "self[key]". Same note ' \ + 'as for\n' \ + ' "__getitem__()". This should only be implemented for ' + 'mappings if\n' + ' the objects support removal of keys, or for sequences if ' + 'elements\n' \ + ' can be removed from the sequence. The same exceptions ' + 'should be\n' + ' raised for improper *key* values as for the ' + '"__getitem__()" method.\n' + '\n' + 'object.__missing__(self, key)\n' + '\n' + ' Called by "dict"."__getitem__()" to implement "self[key]" ' + 'for dict\n' + ' subclasses when key is not in the dictionary.\n' \ + '\n' + 'object.__iter__(self)\n' + '\n' + ' This method is called when an *iterator* is required for ' + 'a\n' \ + ' container. This method should return a new iterator ' + 'object that can\n' \ + ' iterate over all the objects in the container. For ' + 'mappings, it\n' + ' should iterate over the keys of the container.\n' + '\n' + 'object.__reversed__(self)\n' + '\n' \ + ' Called (if present) by the "reversed()" built-in to ' + 'implement\n' + ' reverse iteration. It should return a new iterator ' + 'object that\n' + ' iterates over all the objects in the container in reverse ' + 'order.\n' + '\n' + ' If the "__reversed__()" method is not provided, the ' + '"reversed()"\n' + ' built-in will fall back to using the sequence protocol ' + '("__len__()"\n' + ' and "__getitem__()"). Objects that support the sequence ' + 'protocol\n' + ' should only provide "__reversed__()" if they can provide ' + 'an\n' \ + ' implementation that is more efficient than the one ' + 'provided by\n' + ' "reversed()".\n' + '\n' \ + 'The membership test operators ("in" and "not in") are ' + 'normally\n' + 'implemented as an iteration through a container. However, ' + 'container\n' + 'objects can supply the following special method with a more ' + 'efficient\n' + 'implementation, which also does not require the object be ' + 'iterable.\n' + '\n' + 'object.__contains__(self, item)\n' + '\n' + ' Called to implement membership test operators. Should ' + 'return true\n' + ' if *item* is in *self*, false otherwise. For mapping ' + 'objects, this\n' + ' should consider the keys of the mapping rather than the ' + 'values or\n' + ' the key-item pairs.\n' + '\n' \ + ' For objects that don’t define "__contains__()", the ' + 'membership test\n' \ + ' first tries iteration via "__iter__()", then the old ' + 'sequence\n' + ' iteration protocol via "__getitem__()", see this section ' + 'in the\n' \ + ' language reference.\n' \ + '\n' \ + '\n' + 'Emulating numeric types\n' \ + '=======================\n' + '\n' + 'The following methods can be defined to emulate numeric ' + 'objects.\n' + 'Methods corresponding to operations that are not supported ' + 'by the\n' \ + 'particular kind of number implemented (e.g., bitwise ' + 'operations for\n' + 'non-integral numbers) should be left undefined.\n' + '\n' + 'object.__add__(self, other)\n' \ + 'object.__sub__(self, other)\n' + 'object.__mul__(self, other)\n' + 'object.__matmul__(self, other)\n' + 'object.__truediv__(self, other)\n' + 'object.__floordiv__(self, other)\n' \ + 'object.__mod__(self, other)\n' + 'object.__divmod__(self, other)\n' + 'object.__pow__(self, other[, modulo])\n' + 'object.__lshift__(self, other)\n' \ + 'object.__rshift__(self, other)\n' + 'object.__and__(self, other)\n' + 'object.__xor__(self, other)\n' + 'object.__or__(self, other)\n' + '\n' \ + ' These methods are called to implement the binary ' + 'arithmetic\n' + ' operations ("+", "-", "*", "@", "/", "//", "%", ' + '"divmod()",\n' + ' "pow()", "**", "<<", ">>", "&", "^", "|"). For instance, ' + 'to\n' + ' evaluate the expression "x + y", where *x* is an instance ' + 'of a\n' + ' class that has an "__add__()" method, "type(x).__add__(x, ' + 'y)" is\n' + ' called. The "__divmod__()" method should be the ' + 'equivalent to\n' + ' using "__floordiv__()" and "__mod__()"; it should not be ' + 'related to\n' + ' "__truediv__()". Note that "__pow__()" should be defined ' + 'to accept\n' + ' an optional third argument if the ternary version of the ' + 'built-in\n' + ' "pow()" function is to be supported.\n' + '\n' \ + ' If one of those methods does not support the operation ' + 'with the\n' + ' supplied arguments, it should return "NotImplemented".\n' + '\n' + 'object.__radd__(self, other)\n' + 'object.__rsub__(self, other)\n' + 'object.__rmul__(self, other)\n' + 'object.__rmatmul__(self, other)\n' + 'object.__rtruediv__(self, other)\n' \ + 'object.__rfloordiv__(self, other)\n' \ + 'object.__rmod__(self, other)\n' + 'object.__rdivmod__(self, other)\n' + 'object.__rpow__(self, other[, modulo])\n' \ + 'object.__rlshift__(self, other)\n' + 'object.__rrshift__(self, other)\n' + 'object.__rand__(self, other)\n' + 'object.__rxor__(self, other)\n' + 'object.__ror__(self, other)\n' \ + '\n' + ' These methods are called to implement the binary ' + 'arithmetic\n' \ + ' operations ("+", "-", "*", "@", "/", "//", "%", ' + '"divmod()",\n' + ' "pow()", "**", "<<", ">>", "&", "^", "|") with reflected ' + '(swapped)\n' + ' operands. These functions are only called if the left ' \ + 'operand does\n' + ' not support the corresponding operation [3] and the ' + 'operands are of\n' + ' different types. [4] For instance, to evaluate the ' + 'expression "x -\n' \ + ' y", where *y* is an instance of a class that has an ' + '"__rsub__()"\n' + ' method, "type(y).__rsub__(y, x)" is called if ' + '"type(x).__sub__(x,\n' \ + ' y)" returns "NotImplemented".\n' + '\n' \ + ' Note that ternary "pow()" will not try calling ' + '"__rpow__()" (the\n' + ' coercion rules would become too complicated).\n' + '\n' + ' Note:\n' + '\n' + ' If the right operand’s type is a subclass of the left ' + 'operand’s\n' + ' type and that subclass provides a different ' + 'implementation of the\n' + ' reflected method for the operation, this method will be ' + 'called\n' + ' before the left operand’s non-reflected method. This ' + 'behavior\n' + ' allows subclasses to override their ancestors’ ' \ + 'operations.\n' + '\n' + 'object.__iadd__(self, other)\n' + 'object.__isub__(self, other)\n' + 'object.__imul__(self, other)\n' + 'object.__imatmul__(self, other)\n' + 'object.__itruediv__(self, other)\n' + 'object.__ifloordiv__(self, other)\n' + 'object.__imod__(self, other)\n' + 'object.__ipow__(self, other[, modulo])\n' \ + 'object.__ilshift__(self, other)\n' + 'object.__irshift__(self, other)\n' \ + 'object.__iand__(self, other)\n' + 'object.__ixor__(self, other)\n' + 'object.__ior__(self, other)\n' + '\n' + ' These methods are called to implement the augmented ' + 'arithmetic\n' + ' assignments ("+=", "-=", "*=", "@=", "/=", "//=", "%=", ' + '"**=",\n' + ' "<<=", ">>=", "&=", "^=", "|="). These methods should ' \ + 'attempt to\n' \ + ' do the operation in-place (modifying *self*) and return ' \ + 'the result\n' + ' (which could be, but does not have to be, *self*). If a ' \ + 'specific\n' + ' method is not defined, or if that method returns ' + '"NotImplemented",\n' \ + ' the augmented assignment falls back to the normal ' + 'methods. For\n' \ + ' instance, if *x* is an instance of a class with an ' + '"__iadd__()"\n' + ' method, "x += y" is equivalent to "x = x.__iadd__(y)" . ' + 'If\n' + ' "__iadd__()" does not exist, or if "x.__iadd__(y)" ' + 'returns\n' + ' "NotImplemented", "x.__add__(y)" and "y.__radd__(x)" are\n' \ + ' considered, as with the evaluation of "x + y". In ' + 'certain\n' + ' situations, augmented assignment can result in unexpected ' + 'errors\n' + ' (see Why does a_tuple[i] += [‘item’] raise an exception ' + 'when the\n' + ' addition works?), but this behavior is in fact part of ' + 'the data\n' + ' model.\n' + '\n' + 'object.__neg__(self)\n' + 'object.__pos__(self)\n' + 'object.__abs__(self)\n' + 'object.__invert__(self)\n' + '\n' + ' Called to implement the unary arithmetic operations ("-", ' + '"+",\n' + ' "abs()" and "~").\n' + '\n' + 'object.__complex__(self)\n' \ + 'object.__int__(self)\n' + 'object.__float__(self)\n' + '\n' + ' Called to implement the built-in functions "complex()", ' + '"int()" and\n' + ' "float()". Should return a value of the appropriate ' + 'type.\n' + '\n' \ + 'object.__index__(self)\n' + '\n' + ' Called to implement "operator.index()", and whenever ' + 'Python needs\n' + ' to losslessly convert the numeric object to an integer ' + 'object (such\n' + ' as in slicing, or in the built-in "bin()", "hex()" and ' + '"oct()"\n' + ' functions). Presence of this method indicates that the ' + 'numeric\n' + ' object is an integer type. Must return an integer.\n' + '\n' + ' If "__int__()", "__float__()" and "__complex__()" are not ' + 'defined\n' + ' then corresponding built-in functions "int()", "float()" ' + 'and\n' + ' "complex()" fall back to "__index__()".\n' \ + '\n' + 'object.__round__(self[, ndigits])\n' + 'object.__trunc__(self)\n' \ + 'object.__floor__(self)\n' + 'object.__ceil__(self)\n' + '\n' \ + ' Called to implement the built-in function "round()" and ' + '"math"\n' \ + ' functions "trunc()", "floor()" and "ceil()". Unless ' + '*ndigits* is\n' \ + ' passed to "__round__()" all these methods should return ' \ + 'the value\n' \ + ' of the object truncated to an "Integral" (typically an ' + '"int").\n' + '\n' + ' The built-in function "int()" falls back to "__trunc__()" ' + 'if\n' + ' neither "__int__()" nor "__index__()" is defined.\n' + '\n' + ' Changed in version 3.11: The delegation of "int()" to ' + '"__trunc__()"\n' + ' is deprecated.\n' + '\n' + '\n' + 'With Statement Context Managers\n' + '===============================\n' + '\n' + 'A *context manager* is an object that defines the runtime ' + 'context to\n' + 'be established when executing a "with" statement. The ' + 'context manager\n' + 'handles the entry into, and the exit from, the desired ' + 'runtime context\n' + 'for the execution of the block of code. Context managers ' \ + 'are normally\n' + 'invoked using the "with" statement (described in section The ' + 'with\n' + 'statement), but can also be used by directly invoking their ' + 'methods.\n' + '\n' + 'Typical uses of context managers include saving and ' \ + 'restoring various\n' \ + 'kinds of global state, locking and unlocking resources, ' + 'closing opened\n' \ + 'files, etc.\n' + '\n' + 'For more information on context managers, see Context ' + 'Manager Types.\n' + 'The "object" class itself does not provide the context ' + 'manager\n' \ + 'methods.\n' + '\n' + 'object.__enter__(self)\n' + '\n' \ + ' Enter the runtime context related to this object. The ' + '"with"\n' + ' statement will bind this method’s return value to the ' + 'target(s)\n' \ + ' specified in the "as" clause of the statement, if any.\n' + '\n' + 'object.__exit__(self, exc_type, exc_value, traceback)\n' + '\n' + ' Exit the runtime context related to this object. The ' + 'parameters\n' + ' describe the exception that caused the context to be ' + 'exited. If the\n' + ' context was exited without an exception, all three ' + 'arguments will\n' \ + ' be "None".\n' + '\n' + ' If an exception is supplied, and the method wishes to ' + 'suppress the\n' + ' exception (i.e., prevent it from being propagated), it ' + 'should\n' + ' return a true value. Otherwise, the exception will be ' + 'processed\n' + ' normally upon exit from this method.\n' + '\n' + ' Note that "__exit__()" methods should not reraise the ' + 'passed-in\n' + ' exception; this is the caller’s responsibility.\n' + '\n' + 'See also:\n' + '\n' + ' **PEP 343** - The “with” statement\n' + ' The specification, background, and examples for the ' + 'Python "with"\n' + ' statement.\n' + '\n' \ + '\n' + 'Customizing positional arguments in class pattern matching\n' + '==========================================================\n' \ + '\n' + 'When using a class name in a pattern, positional arguments ' + 'in the\n' \ + 'pattern are not allowed by default, i.e. "case MyClass(x, ' + 'y)" is\n' + 'typically invalid without special support in "MyClass". To ' + 'be able to\n' \ + 'use that kind of pattern, the class needs to define a ' + '*__match_args__*\n' + 'attribute.\n' + '\n' + 'object.__match_args__\n' \ + '\n' \ + ' This class variable can be assigned a tuple of strings. ' \ + 'When this\n' \ + ' class is used in a class pattern with positional ' + 'arguments, each\n' + ' positional argument will be converted into a keyword ' + 'argument,\n' \ + ' using the corresponding value in *__match_args__* as the ' + 'keyword.\n' + ' The absence of this attribute is equivalent to setting it ' \ + 'to "()".\n' \ + '\n' + 'For example, if "MyClass.__match_args__" is "("left", ' + '"center",\n' + '"right")" that means that "case MyClass(x, y)" is equivalent ' + 'to "case\n' + 'MyClass(left=x, center=y)". Note that the number of ' + 'arguments in the\n' + 'pattern must be smaller than or equal to the number of ' + 'elements in\n' + '*__match_args__*; if it is larger, the pattern match attempt ' + 'will\n' + 'raise a "TypeError".\n' \ + '\n' + 'Added in version 3.10.\n' + '\n' + 'See also:\n' + '\n' + ' **PEP 634** - Structural Pattern Matching\n' \ + ' The specification for the Python "match" statement.\n' + '\n' + '\n' \ + 'Emulating buffer types\n' + '======================\n' + '\n' \ + 'The buffer protocol provides a way for Python objects to ' + 'expose\n' \ + 'efficient access to a low-level memory array. This protocol ' + 'is\n' \ + 'implemented by builtin types such as "bytes" and ' + '"memoryview", and\n' + 'third-party libraries may define additional buffer types.\n' + '\n' + 'While buffer types are usually implemented in C, it is also ' + 'possible\n' + 'to implement the protocol in Python.\n' + '\n' + 'object.__buffer__(self, flags)\n' + '\n' + ' Called when a buffer is requested from *self* (for ' + 'example, by the\n' + ' "memoryview" constructor). The *flags* argument is an ' + 'integer\n' + ' representing the kind of buffer requested, affecting for ' + 'example\n' + ' whether the returned buffer is read-only or writable.\n' + ' "inspect.BufferFlags" provides a convenient way to ' + 'interpret the\n' + ' flags. The method must return a "memoryview" object.\n' + '\n' + 'object.__release_buffer__(self, buffer)\n' \ + '\n' + ' Called when a buffer is no longer needed. The *buffer* ' + 'argument is\n' + ' a "memoryview" object that was previously returned by\n' + ' "__buffer__()". The method must release any resources ' \ + 'associated\n' + ' with the buffer. This method should return "None". Buffer ' \ + 'objects\n' + ' that do not need to perform any cleanup are not required ' + 'to\n' + ' implement this method.\n' + '\n' + 'Added in version 3.12.\n' + '\n' + 'See also:\n' \ + '\n' + ' **PEP 688** - Making the buffer protocol accessible in ' + 'Python\n' + ' Introduces the Python "__buffer__" and ' + '"__release_buffer__"\n' \ + ' methods.\n' + '\n' + ' "collections.abc.Buffer"\n' \ + ' ABC for buffer types.\n' + '\n' + '\n' + 'Special method lookup\n' + '=====================\n' + '\n' + 'For custom classes, implicit invocations of special methods ' + 'are only\n' + 'guaranteed to work correctly if defined on an object’s type, ' + 'not in\n' + 'the object’s instance dictionary. That behaviour is the ' + 'reason why\n' + 'the following code raises an exception:\n' \ + '\n' + ' >>> class C:\n' + ' ... pass\n' \ + ' ...\n' + ' >>> c = C()\n' + ' >>> c.__len__ = lambda: 5\n' + ' >>> len(c)\n' \ + ' Traceback (most recent call last):\n' + ' File "", line 1, in \n' + " TypeError: object of type 'C' has no len()\n" + '\n' \ + 'The rationale behind this behaviour lies with a number of ' + 'special\n' \ + 'methods such as "__hash__()" and "__repr__()" that are ' + 'implemented by\n' \ + 'all objects, including type objects. If the implicit lookup ' + 'of these\n' \ + 'methods used the conventional lookup process, they would ' + 'fail when\n' \ + 'invoked on the type object itself:\n' + '\n' + ' >>> 1 .__hash__() == hash(1)\n' + ' True\n' + ' >>> int.__hash__() == hash(int)\n' + ' Traceback (most recent call last):\n' + ' File "", line 1, in \n' + " TypeError: descriptor '__hash__' of 'int' object needs an " + 'argument\n' + '\n' + 'Incorrectly attempting to invoke an unbound method of a ' + 'class in this\n' + 'way is sometimes referred to as ‘metaclass confusion’, and ' + 'is avoided\n' + 'by bypassing the instance when looking up special methods:\n' + '\n' + ' >>> type(1).__hash__(1) == hash(1)\n' + ' True\n' \ + ' >>> type(int).__hash__(int) == hash(int)\n' + ' True\n' + '\n' \ + 'In addition to bypassing any instance attributes in the ' + 'interest of\n' \ + 'correctness, implicit special method lookup generally also ' \ + 'bypasses\n' + 'the "__getattribute__()" method even of the object’s ' \ + 'metaclass:\n' + '\n' + ' >>> class Meta(type):\n' + ' ... def __getattribute__(*args):\n' + ' ... print("Metaclass getattribute invoked")\n' + ' ... return type.__getattribute__(*args)\n' + ' ...\n' \ + ' >>> class C(object, metaclass=Meta):\n' + ' ... def __len__(self):\n' + ' ... return 10\n' + ' ... def __getattribute__(*args):\n' + ' ... print("Class getattribute invoked")\n' \ + ' ... return object.__getattribute__(*args)\n' + ' ...\n' \ + ' >>> c = C()\n' + ' >>> c.__len__() # Explicit lookup via ' \ + 'instance\n' + ' Class getattribute invoked\n' + ' 10\n' \ + ' >>> type(c).__len__(c) # Explicit lookup via ' + 'type\n' + ' Metaclass getattribute invoked\n' + ' 10\n' + ' >>> len(c) # Implicit lookup\n' + ' 10\n' + '\n' + 'Bypassing the "__getattribute__()" machinery in this fashion ' + 'provides\n' + 'significant scope for speed optimisations within the ' + 'interpreter, at\n' + 'the cost of some flexibility in the handling of special ' + 'methods (the\n' + 'special method *must* be set on the class object itself in ' + 'order to be\n' + 'consistently invoked by the interpreter).\n', + 'string-methods': 'String Methods\n' \ + '**************\n' + '\n' \ + 'Strings implement all of the common sequence operations, ' \ + 'along with\n' + 'the additional methods described below.\n' + '\n' + 'Strings also support two styles of string formatting, one ' + 'providing a\n' + 'large degree of flexibility and customization (see ' \ + '"str.format()",\n' + 'Format String Syntax and Custom String Formatting) and the ' + 'other based\n' + 'on C "printf" style formatting that handles a narrower ' \ + 'range of types\n' + 'and is slightly harder to use correctly, but is often ' \ + 'faster for the\n' + 'cases it can handle (printf-style String Formatting).\n' \ + '\n' + 'The Text Processing Services section of the standard ' \ + 'library covers a\n' + 'number of other modules that provide various text related ' + 'utilities\n' + '(including regular expression support in the "re" ' + 'module).\n' + '\n' + 'str.capitalize()\n' + '\n' + ' Return a copy of the string with its first character ' + 'capitalized\n' + ' and the rest lowercased.\n' \ + '\n' + ' Changed in version 3.8: The first character is now put ' \ + 'into\n' + ' titlecase rather than uppercase. This means that ' + 'characters like\n' + ' digraphs will only have their first letter capitalized, ' + 'instead of\n' + ' the full character.\n' + '\n' + 'str.casefold()\n' + '\n' \ + ' Return a casefolded copy of the string. Casefolded ' + 'strings may be\n' \ + ' used for caseless matching.\n' + '\n' + ' Casefolding is similar to lowercasing but more ' \ + 'aggressive because\n' + ' it is intended to remove all case distinctions in a ' \ + 'string. For\n' \ + ' example, the German lowercase letter "\'ß\'" is ' + 'equivalent to ""ss"".\n' + ' Since it is already lowercase, "lower()" would do ' + 'nothing to "\'ß\'";\n' + ' "casefold()" converts it to ""ss"".\n' + '\n' + ' The casefolding algorithm is described in section 3.13 ' + '‘Default\n' + ' Case Folding’ of the Unicode Standard.\n' \ + '\n' + ' Added in version 3.3.\n' + '\n' + 'str.center(width[, fillchar])\n' + '\n' + ' Return centered in a string of length *width*. Padding ' + 'is done\n' \ + ' using the specified *fillchar* (default is an ASCII ' \ + 'space). The\n' + ' original string is returned if *width* is less than or ' + 'equal to\n' + ' "len(s)".\n' + '\n' \ + 'str.count(sub[, start[, end]])\n' \ + '\n' + ' Return the number of non-overlapping occurrences of ' + 'substring *sub*\n' + ' in the range [*start*, *end*]. Optional arguments ' + '*start* and\n' \ + ' *end* are interpreted as in slice notation.\n' + '\n' \ + ' If *sub* is empty, returns the number of empty strings ' + 'between\n' \ + ' characters which is the length of the string plus one.\n' + '\n' \ + "str.encode(encoding='utf-8', errors='strict')\n" + '\n' + ' Return the string encoded to "bytes".\n' + '\n' + ' *encoding* defaults to "\'utf-8\'"; see Standard ' \ + 'Encodings for\n' + ' possible values.\n' + '\n' \ + ' *errors* controls how encoding errors are handled. If ' + '"\'strict\'"\n' \ + ' (the default), a "UnicodeError" exception is raised. ' + 'Other possible\n' \ + ' values are "\'ignore\'", "\'replace\'", ' + '"\'xmlcharrefreplace\'",\n' \ + ' "\'backslashreplace\'" and any other name registered ' + 'via\n' \ + ' "codecs.register_error()". See Error Handlers for ' + 'details.\n' \ + '\n' + ' For performance reasons, the value of *errors* is not ' \ + 'checked for\n' + ' validity unless an encoding error actually occurs, ' + 'Python\n' + ' Development Mode is enabled or a debug build is used.\n' + '\n' \ + ' Changed in version 3.1: Added support for keyword ' \ + 'arguments.\n' \ + '\n' + ' Changed in version 3.9: The value of the *errors* ' \ + 'argument is now\n' + ' checked in Python Development Mode and in debug mode.\n' + '\n' + 'str.endswith(suffix[, start[, end]])\n' + '\n' + ' Return "True" if the string ends with the specified ' + '*suffix*,\n' + ' otherwise return "False". *suffix* can also be a tuple ' + 'of suffixes\n' + ' to look for. With optional *start*, test beginning at ' + 'that\n' + ' position. With optional *end*, stop comparing at that ' + 'position.\n' + '\n' + 'str.expandtabs(tabsize=8)\n' + '\n' + ' Return a copy of the string where all tab characters ' \ + 'are replaced\n' \ + ' by one or more spaces, depending on the current column ' + 'and the\n' \ + ' given tab size. Tab positions occur every *tabsize* ' + 'characters\n' \ + ' (default is 8, giving tab positions at columns 0, 8, 16 ' \ + 'and so on).\n' + ' To expand the string, the current column is set to zero ' \ + 'and the\n' + ' string is examined character by character. If the ' \ + 'character is a\n' + ' tab ("\\t"), one or more space characters are inserted ' + 'in the result\n' + ' until the current column is equal to the next tab ' + 'position. (The\n' + ' tab character itself is not copied.) If the character ' + 'is a newline\n' + ' ("\\n") or return ("\\r"), it is copied and the current ' \ + 'column is\n' + ' reset to zero. Any other character is copied unchanged ' \ + 'and the\n' + ' current column is incremented by one regardless of how ' \ + 'the\n' + ' character is represented when printed.\n' \ + '\n' + " >>> '01\\t012\\t0123\\t01234'.expandtabs()\n" + " '01 012 0123 01234'\n" + " >>> '01\\t012\\t0123\\t01234'.expandtabs(4)\n" \ + " '01 012 0123 01234'\n" + '\n' \ + 'str.find(sub[, start[, end]])\n' + '\n' + ' Return the lowest index in the string where substring ' + '*sub* is\n' + ' found within the slice "s[start:end]". Optional ' + 'arguments *start*\n' \ + ' and *end* are interpreted as in slice notation. Return ' + '"-1" if\n' \ + ' *sub* is not found.\n' + '\n' \ + ' Note:\n' \ + '\n' + ' The "find()" method should be used only if you need ' + 'to know the\n' + ' position of *sub*. To check if *sub* is a substring ' + 'or not, use\n' + ' the "in" operator:\n' + '\n' \ + " >>> 'Py' in 'Python'\n" + ' True\n' \ + '\n' + 'str.format(*args, **kwargs)\n' \ + '\n' + ' Perform a string formatting operation. The string on ' \ + 'which this\n' + ' method is called can contain literal text or ' + 'replacement fields\n' + ' delimited by braces "{}". Each replacement field ' \ + 'contains either\n' + ' the numeric index of a positional argument, or the name ' \ + 'of a\n' + ' keyword argument. Returns a copy of the string where ' \ + 'each\n' + ' replacement field is replaced with the string value of ' \ + 'the\n' + ' corresponding argument.\n' + '\n' \ + ' >>> "The sum of 1 + 2 is {0}".format(1+2)\n' + " 'The sum of 1 + 2 is 3'\n" + '\n' \ + ' See Format String Syntax for a description of the ' + 'various\n' + ' formatting options that can be specified in format ' + 'strings.\n' + '\n' \ + ' Note:\n' + '\n' + ' When formatting a number ("int", "float", "complex",\n' \ + ' "decimal.Decimal" and subclasses) with the "n" type ' + '(ex:\n' + ' "\'{:n}\'.format(1234)"), the function temporarily ' + 'sets the\n' + ' "LC_CTYPE" locale to the "LC_NUMERIC" locale to ' + 'decode\n' + ' "decimal_point" and "thousands_sep" fields of ' + '"localeconv()" if\n' + ' they are non-ASCII or longer than 1 byte, and the ' + '"LC_NUMERIC"\n' \ + ' locale is different than the "LC_CTYPE" locale. This ' + 'temporary\n' \ + ' change affects other threads.\n' + '\n' \ + ' Changed in version 3.7: When formatting a number with ' + 'the "n" type,\n' \ + ' the function sets temporarily the "LC_CTYPE" locale to ' + 'the\n' \ + ' "LC_NUMERIC" locale in some cases.\n' \ + '\n' + 'str.format_map(mapping)\n' + '\n' + ' Similar to "str.format(**mapping)", except that ' + '"mapping" is used\n' \ + ' directly and not copied to a "dict". This is useful if ' + 'for example\n' \ + ' "mapping" is a dict subclass:\n' + '\n' + ' >>> class Default(dict):\n' \ + ' ... def __missing__(self, key):\n' + ' ... return key\n' \ + ' ...\n' \ + " >>> '{name} was born in " + "{country}'.format_map(Default(name='Guido'))\n" + " 'Guido was born in country'\n" + '\n' + ' Added in version 3.2.\n' \ + '\n' + 'str.index(sub[, start[, end]])\n' + '\n' + ' Like "find()", but raise "ValueError" when the ' + 'substring is not\n' \ + ' found.\n' \ + '\n' \ + 'str.isalnum()\n' + '\n' + ' Return "True" if all characters in the string are ' + 'alphanumeric and\n' + ' there is at least one character, "False" otherwise. A ' + 'character\n' + ' "c" is alphanumeric if one of the following returns ' + '"True":\n' + ' "c.isalpha()", "c.isdecimal()", "c.isdigit()", or ' + '"c.isnumeric()".\n' + '\n' + 'str.isalpha()\n' + '\n' + ' Return "True" if all characters in the string are ' + 'alphabetic and\n' + ' there is at least one character, "False" otherwise. ' + 'Alphabetic\n' \ + ' characters are those characters defined in the Unicode ' + 'character\n' + ' database as “Letter”, i.e., those with general category ' + 'property\n' \ + ' being one of “Lm”, “Lt”, “Lu”, “Ll”, or “Lo”. Note ' + 'that this is\n' \ + ' different from the Alphabetic property defined in the ' + 'section 4.10\n' \ + ' ‘Letters, Alphabetic, and Ideographic’ of the Unicode ' + 'Standard.\n' \ + '\n' \ + 'str.isascii()\n' + '\n' + ' Return "True" if the string is empty or all characters ' + 'in the\n' \ + ' string are ASCII, "False" otherwise. ASCII characters ' + 'have code\n' \ + ' points in the range U+0000-U+007F.\n' + '\n' + ' Added in version 3.7.\n' + '\n' + 'str.isdecimal()\n' + '\n' \ + ' Return "True" if all characters in the string are ' + 'decimal\n' \ + ' characters and there is at least one character, "False" ' + 'otherwise.\n' \ + ' Decimal characters are those that can be used to form ' \ + 'numbers in\n' + ' base 10, e.g. U+0660, ARABIC-INDIC DIGIT ZERO. ' + 'Formally a decimal\n' + ' character is a character in the Unicode General ' + 'Category “Nd”.\n' \ + '\n' + 'str.isdigit()\n' + '\n' + ' Return "True" if all characters in the string are ' + 'digits and there\n' + ' is at least one character, "False" otherwise. Digits ' \ + 'include\n' + ' decimal characters and digits that need special ' + 'handling, such as\n' + ' the compatibility superscript digits. This covers ' \ + 'digits which\n' + ' cannot be used to form numbers in base 10, like the ' + 'Kharosthi\n' + ' numbers. Formally, a digit is a character that has the ' \ + 'property\n' + ' value Numeric_Type=Digit or Numeric_Type=Decimal.\n' + '\n' \ + 'str.isidentifier()\n' + '\n' + ' Return "True" if the string is a valid identifier ' + 'according to the\n' + ' language definition, section Identifiers and keywords.\n' + '\n' + ' "keyword.iskeyword()" can be used to test whether ' + 'string "s" is a\n' + ' reserved identifier, such as "def" and "class".\n' + '\n' + ' Example:\n' + '\n' \ + ' >>> from keyword import iskeyword\n' \ + '\n' \ + " >>> 'hello'.isidentifier(), iskeyword('hello')\n" + ' (True, False)\n' \ + " >>> 'def'.isidentifier(), iskeyword('def')\n" + ' (True, True)\n' \ + '\n' + 'str.islower()\n' + '\n' + ' Return "True" if all cased characters [4] in the string ' + 'are\n' \ + ' lowercase and there is at least one cased character, ' + '"False"\n' \ + ' otherwise.\n' \ + '\n' \ + 'str.isnumeric()\n' + '\n' + ' Return "True" if all characters in the string are ' + 'numeric\n' + ' characters, and there is at least one character, ' + '"False" otherwise.\n' \ + ' Numeric characters include digit characters, and all ' + 'characters\n' + ' that have the Unicode numeric value property, e.g. ' \ + 'U+2155, VULGAR\n' + ' FRACTION ONE FIFTH. Formally, numeric characters are ' \ + 'those with\n' + ' the property value Numeric_Type=Digit, ' + 'Numeric_Type=Decimal or\n' + ' Numeric_Type=Numeric.\n' + '\n' \ + 'str.isprintable()\n' + '\n' + ' Return "True" if all characters in the string are ' + 'printable or the\n' \ + ' string is empty, "False" otherwise. Nonprintable ' + 'characters are\n' \ + ' those characters defined in the Unicode character ' \ + 'database as\n' \ + ' “Other” or “Separator”, excepting the ASCII space ' + '(0x20) which is\n' \ + ' considered printable. (Note that printable characters ' + 'in this\n' + ' context are those which should not be escaped when ' + '"repr()" is\n' + ' invoked on a string. It has no bearing on the handling ' + 'of strings\n' \ + ' written to "sys.stdout" or "sys.stderr".)\n' + '\n' + 'str.isspace()\n' \ + '\n' + ' Return "True" if there are only whitespace characters ' + 'in the string\n' + ' and there is at least one character, "False" ' \ + 'otherwise.\n' + '\n' + ' A character is *whitespace* if in the Unicode character ' \ + 'database\n' + ' (see "unicodedata"), either its general category is ' + '"Zs"\n' \ + ' (“Separator, space”), or its bidirectional class is one ' + 'of "WS",\n' \ + ' "B", or "S".\n' + '\n' + 'str.istitle()\n' + '\n' \ + ' Return "True" if the string is a titlecased string and ' + 'there is at\n' + ' least one character, for example uppercase characters ' + 'may only\n' + ' follow uncased characters and lowercase characters only ' + 'cased ones.\n' + ' Return "False" otherwise.\n' + '\n' + 'str.isupper()\n' + '\n' + ' Return "True" if all cased characters [4] in the string ' + 'are\n' + ' uppercase and there is at least one cased character, ' + '"False"\n' + ' otherwise.\n' + '\n' \ + " >>> 'BANANA'.isupper()\n" + ' True\n' + " >>> 'banana'.isupper()\n" + ' False\n' + " >>> 'baNana'.isupper()\n" + ' False\n' + " >>> ' '.isupper()\n" + ' False\n' \ + '\n' + 'str.join(iterable)\n' \ + '\n' + ' Return a string which is the concatenation of the ' + 'strings in\n' + ' *iterable*. A "TypeError" will be raised if there are ' + 'any non-\n' + ' string values in *iterable*, including "bytes" ' + 'objects. The\n' + ' separator between elements is the string providing this ' + 'method.\n' + '\n' \ + 'str.ljust(width[, fillchar])\n' + '\n' + ' Return the string left justified in a string of length ' + '*width*.\n' + ' Padding is done using the specified *fillchar* (default ' \ + 'is an ASCII\n' \ + ' space). The original string is returned if *width* is ' + 'less than or\n' + ' equal to "len(s)".\n' \ + '\n' + 'str.lower()\n' + '\n' + ' Return a copy of the string with all the cased ' + 'characters [4]\n' + ' converted to lowercase.\n' \ + '\n' + ' The lowercasing algorithm used is described in section ' \ + '3.13\n' + ' ‘Default Case Folding’ of the Unicode Standard.\n' \ + '\n' \ + 'str.lstrip([chars])\n' + '\n' + ' Return a copy of the string with leading characters ' \ + 'removed. The\n' + ' *chars* argument is a string specifying the set of ' + 'characters to be\n' + ' removed. If omitted or "None", the *chars* argument ' + 'defaults to\n' + ' removing whitespace. The *chars* argument is not a ' \ + 'prefix; rather,\n' + ' all combinations of its values are stripped:\n' + '\n' + " >>> ' spacious '.lstrip()\n" + " 'spacious '\n" + " >>> 'www.example.com'.lstrip('cmowz.')\n" + " 'example.com'\n" \ + '\n' + ' See "str.removeprefix()" for a method that will remove ' \ + 'a single\n' + ' prefix string rather than all of a set of characters. ' + 'For example:\n' + '\n' + " >>> 'Arthur: three!'.lstrip('Arthur: ')\n" + " 'ee!'\n" + " >>> 'Arthur: three!'.removeprefix('Arthur: ')\n" + " 'three!'\n" \ + '\n' + 'static str.maketrans(x[, y[, z]])\n' + '\n' + ' This static method returns a translation table usable ' + 'for\n' + ' "str.translate()".\n' + '\n' \ + ' If there is only one argument, it must be a dictionary ' + 'mapping\n' \ + ' Unicode ordinals (integers) or characters (strings of ' \ + 'length 1) to\n' + ' Unicode ordinals, strings (of arbitrary lengths) or ' \ + '"None".\n' + ' Character keys will then be converted to ordinals.\n' + '\n' + ' If there are two arguments, they must be strings of ' + 'equal length,\n' + ' and in the resulting dictionary, each character in x ' + 'will be mapped\n' + ' to the character at the same position in y. If there ' + 'is a third\n' + ' argument, it must be a string, whose characters will be ' + 'mapped to\n' + ' "None" in the result.\n' \ + '\n' + 'str.partition(sep)\n' + '\n' + ' Split the string at the first occurrence of *sep*, and ' + 'return a\n' \ + ' 3-tuple containing the part before the separator, the ' + 'separator\n' \ + ' itself, and the part after the separator. If the ' + 'separator is not\n' + ' found, return a 3-tuple containing the string itself, ' + 'followed by\n' + ' two empty strings.\n' \ + '\n' + 'str.removeprefix(prefix, /)\n' + '\n' + ' If the string starts with the *prefix* string, return\n' + ' "string[len(prefix):]". Otherwise, return a copy of the ' + 'original\n' \ + ' string:\n' + '\n' + " >>> 'TestHook'.removeprefix('Test')\n" \ + " 'Hook'\n" + " >>> 'BaseTestCase'.removeprefix('Test')\n" \ + " 'BaseTestCase'\n" \ + '\n' \ + ' Added in version 3.9.\n' + '\n' + 'str.removesuffix(suffix, /)\n' + '\n' + ' If the string ends with the *suffix* string and that ' \ + '*suffix* is\n' + ' not empty, return "string[:-len(suffix)]". Otherwise, ' + 'return a copy\n' + ' of the original string:\n' + '\n' + " >>> 'MiscTests'.removesuffix('Tests')\n" + " 'Misc'\n" + " >>> 'TmpDirMixin'.removesuffix('Tests')\n" + " 'TmpDirMixin'\n" \ + '\n' + ' Added in version 3.9.\n' \ + '\n' + 'str.replace(old, new[, count])\n' + '\n' \ + ' Return a copy of the string with all occurrences of ' + 'substring *old*\n' \ + ' replaced by *new*. If the optional argument *count* is ' + 'given, only\n' + ' the first *count* occurrences are replaced.\n' + '\n' + 'str.rfind(sub[, start[, end]])\n' \ + '\n' + ' Return the highest index in the string where substring ' + '*sub* is\n' + ' found, such that *sub* is contained within ' \ + '"s[start:end]".\n' + ' Optional arguments *start* and *end* are interpreted as ' \ + 'in slice\n' + ' notation. Return "-1" on failure.\n' + '\n' + 'str.rindex(sub[, start[, end]])\n' + '\n' + ' Like "rfind()" but raises "ValueError" when the ' + 'substring *sub* is\n' + ' not found.\n' \ + '\n' + 'str.rjust(width[, fillchar])\n' + '\n' + ' Return the string right justified in a string of length ' + '*width*.\n' + ' Padding is done using the specified *fillchar* (default ' \ + 'is an ASCII\n' + ' space). The original string is returned if *width* is ' + 'less than or\n' + ' equal to "len(s)".\n' + '\n' \ + 'str.rpartition(sep)\n' + '\n' + ' Split the string at the last occurrence of *sep*, and ' + 'return a\n' + ' 3-tuple containing the part before the separator, the ' + 'separator\n' + ' itself, and the part after the separator. If the ' + 'separator is not\n' + ' found, return a 3-tuple containing two empty strings, ' + 'followed by\n' + ' the string itself.\n' \ + '\n' + 'str.rsplit(sep=None, maxsplit=-1)\n' + '\n' \ + ' Return a list of the words in the string, using *sep* ' + 'as the\n' + ' delimiter string. If *maxsplit* is given, at most ' + '*maxsplit* splits\n' + ' are done, the *rightmost* ones. If *sep* is not ' + 'specified or\n' \ + ' "None", any whitespace string is a separator. Except ' + 'for splitting\n' + ' from the right, "rsplit()" behaves like "split()" which ' \ + 'is\n' + ' described in detail below.\n' + '\n' \ + 'str.rstrip([chars])\n' + '\n' + ' Return a copy of the string with trailing characters ' \ + 'removed. The\n' + ' *chars* argument is a string specifying the set of ' + 'characters to be\n' + ' removed. If omitted or "None", the *chars* argument ' \ + 'defaults to\n' + ' removing whitespace. The *chars* argument is not a ' \ + 'suffix; rather,\n' + ' all combinations of its values are stripped:\n' + '\n' \ + " >>> ' spacious '.rstrip()\n" + " ' spacious'\n" + " >>> 'mississippi'.rstrip('ipz')\n" + " 'mississ'\n" \ + '\n' \ + ' See "str.removesuffix()" for a method that will remove ' \ + 'a single\n' + ' suffix string rather than all of a set of characters. ' \ + 'For example:\n' + '\n' + " >>> 'Monty Python'.rstrip(' Python')\n" \ + " 'M'\n" \ + " >>> 'Monty Python'.removesuffix(' Python')\n" + " 'Monty'\n" \ + '\n' \ + 'str.split(sep=None, maxsplit=-1)\n' + '\n' + ' Return a list of the words in the string, using *sep* ' + 'as the\n' + ' delimiter string. If *maxsplit* is given, at most ' + '*maxsplit*\n' \ + ' splits are done (thus, the list will have at most ' \ + '"maxsplit+1"\n' + ' elements). If *maxsplit* is not specified or "-1", ' + 'then there is\n' + ' no limit on the number of splits (all possible splits ' \ + 'are made).\n' + '\n' + ' If *sep* is given, consecutive delimiters are not ' \ + 'grouped together\n' \ + ' and are deemed to delimit empty strings (for example,\n' \ + ' "\'1,,2\'.split(\',\')" returns "[\'1\', \'\', ' + '\'2\']"). The *sep* argument\n' \ + ' may consist of multiple characters as a single ' + 'delimiter (to split\n' \ + ' with multiple delimiters, use "re.split()"). Splitting ' \ + 'an empty\n' + ' string with a specified separator returns "[\'\']".\n' + '\n' + ' For example:\n' + '\n' \ + " >>> '1,2,3'.split(',')\n" + " ['1', '2', '3']\n" + " >>> '1,2,3'.split(',', maxsplit=1)\n" + " ['1', '2,3']\n" + " >>> '1,2,,3,'.split(',')\n" \ + " ['1', '2', '', '3', '']\n" \ + " >>> '1<>2<>3<4'.split('<>')\n" \ + " ['1', '2', '3<4']\n" + '\n' + ' If *sep* is not specified or is "None", a different ' + 'splitting\n' + ' algorithm is applied: runs of consecutive whitespace ' + 'are regarded\n' + ' as a single separator, and the result will contain no ' + 'empty strings\n' + ' at the start or end if the string has leading or ' + 'trailing\n' + ' whitespace. Consequently, splitting an empty string or ' + 'a string\n' \ + ' consisting of just whitespace with a "None" separator ' + 'returns "[]".\n' \ + '\n' + ' For example:\n' + '\n' + " >>> '1 2 3'.split()\n" + " ['1', '2', '3']\n" + " >>> '1 2 3'.split(maxsplit=1)\n" \ + " ['1', '2 3']\n" \ + " >>> ' 1 2 3 '.split()\n" \ + " ['1', '2', '3']\n" + '\n' \ + 'str.splitlines(keepends=False)\n' + '\n' + ' Return a list of the lines in the string, breaking at ' + 'line\n' + ' boundaries. Line breaks are not included in the ' + 'resulting list\n' + ' unless *keepends* is given and true.\n' \ + '\n' + ' This method splits on the following line boundaries. ' \ + 'In\n' + ' particular, the boundaries are a superset of *universal ' \ + 'newlines*.\n' + '\n' + ' ' + '+-------------------------+-------------------------------+\n' + ' | Representation | ' \ + 'Description |\n' + ' ' \ + '|=========================|===============================|\n' + ' | "\\n" | Line ' + 'Feed |\n' + ' ' \ + '+-------------------------+-------------------------------+\n' \ + ' | "\\r" | Carriage ' + 'Return |\n' \ + ' ' + '+-------------------------+-------------------------------+\n' \ + ' | "\\r\\n" | Carriage Return + Line ' \ + 'Feed |\n' \ + ' ' + '+-------------------------+-------------------------------+\n' + ' | "\\v" or "\\x0b" | Line ' + 'Tabulation |\n' + ' ' \ + '+-------------------------+-------------------------------+\n' + ' | "\\f" or "\\x0c" | Form ' + 'Feed |\n' \ + ' ' \ + '+-------------------------+-------------------------------+\n' + ' | "\\x1c" | File ' + 'Separator |\n' \ + ' ' + '+-------------------------+-------------------------------+\n' + ' | "\\x1d" | Group ' + 'Separator |\n' \ + ' ' \ + '+-------------------------+-------------------------------+\n' + ' | "\\x1e" | Record ' + 'Separator |\n' + ' ' \ + '+-------------------------+-------------------------------+\n' + ' | "\\x85" | Next Line (C1 Control ' + 'Code) |\n' + ' ' \ + '+-------------------------+-------------------------------+\n' + ' | "\\u2028" | Line ' + 'Separator |\n' \ + ' ' \ + '+-------------------------+-------------------------------+\n' \ + ' | "\\u2029" | Paragraph ' + 'Separator |\n' + ' ' \ + '+-------------------------+-------------------------------+\n' + '\n' + ' Changed in version 3.2: "\\v" and "\\f" added to list ' + 'of line\n' \ + ' boundaries.\n' + '\n' + ' For example:\n' + '\n' + " >>> 'ab c\\n\\nde fg\\rkl\\r\\n'.splitlines()\n" + " ['ab c', '', 'de fg', 'kl']\n" + " >>> 'ab c\\n\\nde " + "fg\\rkl\\r\\n'.splitlines(keepends=True)\n" + " ['ab c\\n', '\\n', 'de fg\\r', 'kl\\r\\n']\n" \ + '\n' + ' Unlike "split()" when a delimiter string *sep* is ' + 'given, this\n' + ' method returns an empty list for the empty string, and ' + 'a terminal\n' + ' line break does not result in an extra line:\n' \ + '\n' \ + ' >>> "".splitlines()\n' + ' []\n' + ' >>> "One line\\n".splitlines()\n' \ + " ['One line']\n" \ + '\n' + ' For comparison, "split(\'\\n\')" gives:\n' \ + '\n' \ + " >>> ''.split('\\n')\n" + " ['']\n" + " >>> 'Two lines\\n'.split('\\n')\n" + " ['Two lines', '']\n" + '\n' \ + 'str.startswith(prefix[, start[, end]])\n' + '\n' + ' Return "True" if string starts with the *prefix*, ' + 'otherwise return\n' + ' "False". *prefix* can also be a tuple of prefixes to ' \ + 'look for.\n' + ' With optional *start*, test string beginning at that ' + 'position.\n' + ' With optional *end*, stop comparing string at that ' + 'position.\n' + '\n' + 'str.strip([chars])\n' + '\n' \ + ' Return a copy of the string with the leading and ' + 'trailing\n' \ + ' characters removed. The *chars* argument is a string ' + 'specifying the\n' + ' set of characters to be removed. If omitted or "None", ' \ + 'the *chars*\n' + ' argument defaults to removing whitespace. The *chars* ' + 'argument is\n' + ' not a prefix or suffix; rather, all combinations of its ' + 'values are\n' + ' stripped:\n' + '\n' + " >>> ' spacious '.strip()\n" + " 'spacious'\n" + " >>> 'www.example.com'.strip('cmowz.')\n" + " 'example'\n" + '\n' + ' The outermost leading and trailing *chars* argument ' + 'values are\n' + ' stripped from the string. Characters are removed from ' + 'the leading\n' + ' end until reaching a string character that is not ' + 'contained in the\n' + ' set of characters in *chars*. A similar action takes ' + 'place on the\n' + ' trailing end. For example:\n' + '\n' + " >>> comment_string = '#....... Section 3.2.1 Issue " + "#32 .......'\n" + " >>> comment_string.strip('.#! ')\n" \ + " 'Section 3.2.1 Issue #32'\n" + '\n' + 'str.swapcase()\n' + '\n' \ + ' Return a copy of the string with uppercase characters ' + 'converted to\n' \ + ' lowercase and vice versa. Note that it is not ' + 'necessarily true that\n' + ' "s.swapcase().swapcase() == s".\n' + '\n' \ + 'str.title()\n' + '\n' + ' Return a titlecased version of the string where words ' \ + 'start with an\n' \ + ' uppercase character and the remaining characters are ' + 'lowercase.\n' + '\n' + ' For example:\n' \ + '\n' + " >>> 'Hello world'.title()\n" + " 'Hello World'\n" \ + '\n' + ' The algorithm uses a simple language-independent ' + 'definition of a\n' + ' word as groups of consecutive letters. The definition ' \ + 'works in\n' + ' many contexts but it means that apostrophes in ' \ + 'contractions and\n' + ' possessives form word boundaries, which may not be the ' \ + 'desired\n' + ' result:\n' + '\n' + ' >>> "they\'re bill\'s friends from the UK".title()\n' + ' "They\'Re Bill\'S Friends From The Uk"\n' + '\n' + ' The "string.capwords()" function does not have this ' + 'problem, as it\n' + ' splits words on spaces only.\n' \ + '\n' + ' Alternatively, a workaround for apostrophes can be ' \ + 'constructed\n' + ' using regular expressions:\n' + '\n' + ' >>> import re\n' + ' >>> def titlecase(s):\n' + ' ... return re.sub(r"[A-Za-z]+(\'[A-Za-z]+)?",\n' + ' ... lambda mo: ' \ + 'mo.group(0).capitalize(),\n' + ' ... s)\n' \ + ' ...\n' \ + ' >>> titlecase("they\'re bill\'s friends.")\n' + ' "They\'re Bill\'s Friends."\n' + '\n' + 'str.translate(table)\n' \ + '\n' \ + ' Return a copy of the string in which each character has ' \ + 'been mapped\n' + ' through the given translation table. The table must be ' + 'an object\n' + ' that implements indexing via "__getitem__()", typically ' + 'a *mapping*\n' + ' or *sequence*. When indexed by a Unicode ordinal (an ' \ + 'integer), the\n' + ' table object can do any of the following: return a ' \ + 'Unicode ordinal\n' + ' or a string, to map the character to one or more other ' \ + 'characters;\n' \ + ' return "None", to delete the character from the return ' + 'string; or\n' \ + ' raise a "LookupError" exception, to map the character ' \ + 'to itself.\n' + '\n' + ' You can use "str.maketrans()" to create a translation ' + 'map from\n' + ' character-to-character mappings in different formats.\n' + '\n' + ' See also the "codecs" module for a more flexible ' + 'approach to custom\n' \ + ' character mappings.\n' + '\n' \ + 'str.upper()\n' \ + '\n' + ' Return a copy of the string with all the cased ' \ + 'characters [4]\n' + ' converted to uppercase. Note that ' \ + '"s.upper().isupper()" might be\n' \ + ' "False" if "s" contains uncased characters or if the ' + 'Unicode\n' \ + ' category of the resulting character(s) is not “Lu” ' + '(Letter,\n' \ + ' uppercase), but e.g. “Lt” (Letter, titlecase).\n' + '\n' + ' The uppercasing algorithm used is described in section ' \ + '3.13\n' + ' ‘Default Case Folding’ of the Unicode Standard.\n' + '\n' + 'str.zfill(width)\n' + '\n' + ' Return a copy of the string left filled with ASCII ' + '"\'0\'" digits to\n' + ' make a string of length *width*. A leading sign prefix\n' + ' ("\'+\'"/"\'-\'") is handled by inserting the padding ' \ + '*after* the sign\n' \ + ' character rather than before. The original string is ' \ + 'returned if\n' + ' *width* is less than or equal to "len(s)".\n' \ + '\n' + ' For example:\n' + '\n' + ' >>> "42".zfill(5)\n' + " '00042'\n" + ' >>> "-42".zfill(5)\n' \ + " '-0042'\n", + 'strings': 'String and Bytes literals\n' + '*************************\n' + '\n' + 'String literals are described by the following lexical ' \ + 'definitions:\n' + '\n' \ + ' stringliteral ::= [stringprefix](shortstring | longstring)\n' + ' stringprefix ::= "r" | "u" | "R" | "U" | "f" | "F"\n' + ' | "fr" | "Fr" | "fR" | "FR" | "rf" | "rF" | ' + '"Rf" | "RF"\n' + ' shortstring ::= "\'" shortstringitem* "\'" | \'"\' ' + 'shortstringitem* \'"\'\n' + ' longstring ::= "\'\'\'" longstringitem* "\'\'\'" | ' + '\'"""\' longstringitem* \'"""\'\n' + ' shortstringitem ::= shortstringchar | stringescapeseq\n' + ' longstringitem ::= longstringchar | stringescapeseq\n' + ' shortstringchar ::= \n' + ' longstringchar ::= \n' \ + ' stringescapeseq ::= "\\" \n' + '\n' + ' bytesliteral ::= bytesprefix(shortbytes | longbytes)\n' + ' bytesprefix ::= "b" | "B" | "br" | "Br" | "bR" | "BR" | ' \ + '"rb" | "rB" | "Rb" | "RB"\n' + ' shortbytes ::= "\'" shortbytesitem* "\'" | \'"\' ' \ + 'shortbytesitem* \'"\'\n' + ' longbytes ::= "\'\'\'" longbytesitem* "\'\'\'" | \'"""\' ' + 'longbytesitem* \'"""\'\n' + ' shortbytesitem ::= shortbyteschar | bytesescapeseq\n' + ' longbytesitem ::= longbyteschar | bytesescapeseq\n' + ' shortbyteschar ::= \n' + ' longbyteschar ::= \n' \ + ' bytesescapeseq ::= "\\" \n' + '\n' + 'One syntactic restriction not indicated by these productions is ' + 'that\n' + 'whitespace is not allowed between the "stringprefix" or ' + '"bytesprefix"\n' + 'and the rest of the literal. The source character set is defined ' + 'by\n' + 'the encoding declaration; it is UTF-8 if no encoding declaration ' \ + 'is\n' \ + 'given in the source file; see section Encoding declarations.\n' \ + '\n' + 'In plain English: Both types of literals can be enclosed in ' + 'matching\n' + 'single quotes ("\'") or double quotes ("""). They can also be ' \ + 'enclosed\n' + 'in matching groups of three single or double quotes (these are\n' \ + 'generally referred to as *triple-quoted strings*). The backslash ' + '("\\")\n' + 'character is used to give special meaning to otherwise ordinary\n' + 'characters like "n", which means ‘newline’ when escaped ("\\n"). ' + 'It can\n' + 'also be used to escape characters that otherwise have a special\n' + 'meaning, such as newline, backslash itself, or the quote ' + 'character.\n' + 'See escape sequences below for examples.\n' \ + '\n' + 'Bytes literals are always prefixed with "\'b\'" or "\'B\'"; they ' + 'produce\n' + 'an instance of the "bytes" type instead of the "str" type. They ' + 'may\n' \ + 'only contain ASCII characters; bytes with a numeric value of 128 ' \ + 'or\n' \ + 'greater must be expressed with escapes.\n' + '\n' + 'Both string and bytes literals may optionally be prefixed with a\n' + 'letter "\'r\'" or "\'R\'"; such constructs are called *raw ' + 'string\n' + 'literals* and *raw bytes literals* respectively and treat ' + 'backslashes\n' + 'as literal characters. As a result, in raw string literals, ' + '"\'\\U\'"\n' + 'and "\'\\u\'" escapes are not treated specially.\n' + '\n' + 'Added in version 3.3: The "\'rb\'" prefix of raw bytes literals ' + 'has been\n' + 'added as a synonym of "\'br\'".Support for the unicode legacy ' \ + 'literal\n' \ + '("u\'value\'") was reintroduced to simplify the maintenance of ' + 'dual\n' \ + 'Python 2.x and 3.x codebases. See **PEP 414** for more ' + 'information.\n' + '\n' + 'A string literal with "\'f\'" or "\'F\'" in its prefix is a ' \ + '*formatted\n' + 'string literal*; see f-strings. The "\'f\'" may be combined with ' + '"\'r\'",\n' + 'but not with "\'b\'" or "\'u\'", therefore raw formatted strings ' \ + 'are\n' + 'possible, but formatted bytes literals are not.\n' \ + '\n' \ + 'In triple-quoted literals, unescaped newlines and quotes are ' \ + 'allowed\n' + '(and are retained), except that three unescaped quotes in a row\n' + 'terminate the literal. (A “quote” is the character used to open ' + 'the\n' \ + 'literal, i.e. either "\'" or """.)\n' + '\n' + '\n' + 'Escape sequences\n' + '================\n' + '\n' + 'Unless an "\'r\'" or "\'R\'" prefix is present, escape sequences ' + 'in string\n' + 'and bytes literals are interpreted according to rules similar to ' \ + 'those\n' \ + 'used by Standard C. The recognized escape sequences are:\n' + '\n' \ + '+---------------------------+-----------------------------------+---------+\n' \ + '| Escape Sequence | Meaning | ' \ + 'Notes |\n' \ + '|===========================|===================================|=========|\n' + '| "\\" | Backslash and newline ignored ' + '| (1) |\n' + '+---------------------------+-----------------------------------+---------+\n' + '| "\\\\" | Backslash ' \ + '("\\") | |\n' + '+---------------------------+-----------------------------------+---------+\n' + '| "\\\'" | Single quote ' + '("\'") | |\n' + '+---------------------------+-----------------------------------+---------+\n' + '| "\\"" | Double quote (""") ' + '| |\n' \ + '+---------------------------+-----------------------------------+---------+\n' + '| "\\a" | ASCII Bell (BEL) ' + '| |\n' + '+---------------------------+-----------------------------------+---------+\n' \ + '| "\\b" | ASCII Backspace (BS) ' + '| |\n' \ + '+---------------------------+-----------------------------------+---------+\n' \ + '| "\\f" | ASCII Formfeed (FF) ' + '| |\n' \ + '+---------------------------+-----------------------------------+---------+\n' \ + '| "\\n" | ASCII Linefeed (LF) ' + '| |\n' \ + '+---------------------------+-----------------------------------+---------+\n' + '| "\\r" | ASCII Carriage Return (CR) ' \ + '| |\n' + '+---------------------------+-----------------------------------+---------+\n' + '| "\\t" | ASCII Horizontal Tab (TAB) ' \ + '| |\n' \ + '+---------------------------+-----------------------------------+---------+\n' + '| "\\v" | ASCII Vertical Tab (VT) ' + '| |\n' + '+---------------------------+-----------------------------------+---------+\n' \ + '| "\\*ooo*" | Character with octal value *ooo* ' + '| (2,4) |\n' + '+---------------------------+-----------------------------------+---------+\n' + '| "\\x*hh*" | Character with hex value *hh* ' + '| (3,4) |\n' \ + '+---------------------------+-----------------------------------+---------+\n' + '\n' \ + 'Escape sequences only recognized in string literals are:\n' + '\n' + '+---------------------------+-----------------------------------+---------+\n' \ + '| Escape Sequence | Meaning | ' + 'Notes |\n' + '|===========================|===================================|=========|\n' + '| "\\N{*name*}" | Character named *name* in the ' + '| (5) |\n' + '| | Unicode database ' + '| |\n' + '+---------------------------+-----------------------------------+---------+\n' \ + '| "\\u*xxxx*" | Character with 16-bit hex value ' \ + '| (6) |\n' + '| | *xxxx* ' \ + '| |\n' \ + '+---------------------------+-----------------------------------+---------+\n' + '| "\\U*xxxxxxxx*" | Character with 32-bit hex value ' + '| (7) |\n' + '| | *xxxxxxxx* ' + '| |\n' + '+---------------------------+-----------------------------------+---------+\n' + '\n' + 'Notes:\n' \ + '\n' + '1. A backslash can be added at the end of a line to ignore the\n' + ' newline:\n' + '\n' + " >>> 'This string will not include \\\n" + " ... backslashes or newline characters.'\n" + " 'This string will not include backslashes or newline " + "characters.'\n" + '\n' + ' The same result can be achieved using triple-quoted strings, ' + 'or\n' + ' parentheses and string literal concatenation.\n' + '\n' + '2. As in Standard C, up to three octal digits are accepted.\n' \ + '\n' + ' Changed in version 3.11: Octal escapes with value larger than\n' + ' "0o377" produce a "DeprecationWarning".\n' + '\n' + ' Changed in version 3.12: Octal escapes with value larger than\n' + ' "0o377" produce a "SyntaxWarning". In a future Python version ' + 'they\n' + ' will be eventually a "SyntaxError".\n' \ + '\n' + '3. Unlike in Standard C, exactly two hex digits are required.\n' \ + '\n' + '4. In a bytes literal, hexadecimal and octal escapes denote the ' + 'byte\n' \ + ' with the given value. In a string literal, these escapes ' + 'denote a\n' \ + ' Unicode character with the given value.\n' + '\n' + '5. Changed in version 3.3: Support for name aliases [1] has been\n' + ' added.\n' + '\n' \ + '6. Exactly four hex digits are required.\n' + '\n' \ + '7. Any Unicode character can be encoded this way. Exactly eight ' + 'hex\n' + ' digits are required.\n' + '\n' + 'Unlike Standard C, all unrecognized escape sequences are left in ' + 'the\n' + 'string unchanged, i.e., *the backslash is left in the result*. ' + '(This\n' + 'behavior is useful when debugging: if an escape sequence is ' \ + 'mistyped,\n' + 'the resulting output is more easily recognized as broken.) It is ' \ + 'also\n' + 'important to note that the escape sequences only recognized in ' + 'string\n' + 'literals fall into the category of unrecognized escapes for ' \ + 'bytes\n' + 'literals.\n' + '\n' + 'Changed in version 3.6: Unrecognized escape sequences produce a\n' + '"DeprecationWarning".\n' + '\n' \ + 'Changed in version 3.12: Unrecognized escape sequences produce a\n' + '"SyntaxWarning". In a future Python version they will be ' + 'eventually a\n' \ + '"SyntaxError".\n' + '\n' + 'Even in a raw literal, quotes can be escaped with a backslash, ' \ + 'but the\n' + 'backslash remains in the result; for example, "r"\\""" is a ' + 'valid\n' + 'string literal consisting of two characters: a backslash and a ' + 'double\n' \ + 'quote; "r"\\"" is not a valid string literal (even a raw string ' + 'cannot\n' \ + 'end in an odd number of backslashes). Specifically, *a raw ' + 'literal\n' + 'cannot end in a single backslash* (since the backslash would ' + 'escape\n' + 'the following quote character). Note also that a single ' + 'backslash\n' + 'followed by a newline is interpreted as those two characters as ' + 'part\n' + 'of the literal, *not* as a line continuation.\n', + 'subscriptions': 'Subscriptions\n' + '*************\n' \ + '\n' + 'The subscription of an instance of a container class will ' + 'generally\n' + 'select an element from the container. The subscription of a ' + '*generic\n' + 'class* will generally return a GenericAlias object.\n' + '\n' + ' subscription ::= primary "[" flexible_expression_list ' + '"]"\n' + '\n' + 'When an object is subscripted, the interpreter will ' + 'evaluate the\n' + 'primary and the expression list.\n' + '\n' + 'The primary must evaluate to an object that supports ' + 'subscription. An\n' \ + 'object may support subscription through defining one or ' \ + 'both of\n' \ + '"__getitem__()" and "__class_getitem__()". When the primary ' + 'is\n' + 'subscripted, the evaluated result of the expression list ' \ + 'will be\n' \ + 'passed to one of these methods. For more details on when\n' \ + '"__class_getitem__" is called instead of "__getitem__", ' \ + 'see\n' + '__class_getitem__ versus __getitem__.\n' + '\n' \ + 'If the expression list contains at least one comma, or if ' \ + 'any of the\n' + 'expressions are starred, the expression list will evaluate ' + 'to a\n' + '"tuple" containing the items of the expression list. ' + 'Otherwise, the\n' + 'expression list will evaluate to the value of the list’s ' + 'sole member.\n' + '\n' + 'Changed in version 3.11: Expressions in an expression list ' \ + 'may be\n' + 'starred. See **PEP 646**.\n' + '\n' \ + 'For built-in objects, there are two types of objects that ' + 'support\n' \ + 'subscription via "__getitem__()":\n' + '\n' + '1. Mappings. If the primary is a *mapping*, the expression ' + 'list must\n' + ' evaluate to an object whose value is one of the keys of ' \ + 'the\n' + ' mapping, and the subscription selects the value in the ' + 'mapping that\n' + ' corresponds to that key. An example of a builtin mapping ' \ + 'class is\n' \ + ' the "dict" class.\n' + '\n' \ + '2. Sequences. If the primary is a *sequence*, the ' + 'expression list must\n' + ' evaluate to an "int" or a "slice" (as discussed in the ' + 'following\n' + ' section). Examples of builtin sequence classes include ' \ + 'the "str",\n' \ + ' "list" and "tuple" classes.\n' \ + '\n' \ + 'The formal syntax makes no special provision for negative ' + 'indices in\n' \ + '*sequences*. However, built-in sequences all provide a ' + '"__getitem__()"\n' \ + 'method that interprets negative indices by adding the ' + 'length of the\n' \ + 'sequence to the index so that, for example, "x[-1]" selects ' + 'the last\n' + 'item of "x". The resulting value must be a nonnegative ' + 'integer less\n' + 'than the number of items in the sequence, and the ' \ + 'subscription selects\n' \ + 'the item whose index is that value (counting from zero). ' + 'Since the\n' + 'support for negative indices and slicing occurs in the ' + 'object’s\n' + '"__getitem__()" method, subclasses overriding this method ' + 'will need to\n' + 'explicitly add that support.\n' + '\n' + 'A "string" is a special kind of sequence whose items are ' + '*characters*.\n' + 'A character is not a separate data type but a string of ' \ + 'exactly one\n' + 'character.\n', + 'truth': 'Truth Value Testing\n' + '*******************\n' + '\n' + 'Any object can be tested for truth value, for use in an "if" or\n' + '"while" condition or as operand of the Boolean operations below.\n' + '\n' \ + 'By default, an object is considered true unless its class defines\n' + 'either a "__bool__()" method that returns "False" or a "__len__()"\n' + 'method that returns zero, when called with the object. [1] Here ' + 'are\n' + 'most of the built-in objects considered false:\n' + '\n' + '* constants defined to be false: "None" and "False"\n' + '\n' \ + '* zero of any numeric type: "0", "0.0", "0j", "Decimal(0)",\n' + ' "Fraction(0, 1)"\n' + '\n' + '* empty sequences and collections: "\'\'", "()", "[]", "{}", ' \ + '"set()",\n' + ' "range(0)"\n' + '\n' + 'Operations and built-in functions that have a Boolean result ' + 'always\n' + 'return "0" or "False" for false and "1" or "True" for true, unless\n' \ + 'otherwise stated. (Important exception: the Boolean operations ' + '"or"\n' + 'and "and" always return one of their operands.)\n', + 'try': 'The "try" statement\n' + '*******************\n' \ + '\n' + 'The "try" statement specifies exception handlers and/or cleanup code\n' + 'for a group of statements:\n' + '\n' + ' try_stmt ::= try1_stmt | try2_stmt | try3_stmt\n' \ + ' try1_stmt ::= "try" ":" suite\n' + ' ("except" [expression ["as" identifier]] ":" ' + 'suite)+\n' + ' ["else" ":" suite]\n' + ' ["finally" ":" suite]\n' + ' try2_stmt ::= "try" ":" suite\n' + ' ("except" "*" expression ["as" identifier] ":" ' + 'suite)+\n' + ' ["else" ":" suite]\n' + ' ["finally" ":" suite]\n' + ' try3_stmt ::= "try" ":" suite\n' + ' "finally" ":" suite\n' + '\n' + 'Additional information on exceptions can be found in section\n' + 'Exceptions, and information on using the "raise" statement to ' + 'generate\n' + 'exceptions may be found in section The raise statement.\n' + '\n' + '\n' + '"except" clause\n' + '===============\n' + '\n' + 'The "except" clause(s) specify one or more exception handlers. When ' + 'no\n' + 'exception occurs in the "try" clause, no exception handler is\n' \ + 'executed. When an exception occurs in the "try" suite, a search for ' + 'an\n' + 'exception handler is started. This search inspects the "except"\n' + 'clauses in turn until one is found that matches the exception. An\n' + 'expression-less "except" clause, if present, must be last; it ' + 'matches\n' \ + 'any exception.\n' + '\n' + 'For an "except" clause with an expression, the expression must\n' + 'evaluate to an exception type or a tuple of exception types. The\n' + 'raised exception matches an "except" clause whose expression ' + 'evaluates\n' + 'to the class or a *non-virtual base class* of the exception object, ' 'or\n' - ' indirect) subclass of *class*. If defined, called to ' - 'implement\n' - ' "issubclass(subclass, class)".\n' + 'to a tuple that contains such a class.\n' '\n' - 'Note that these methods are looked up on the type ' - '(metaclass) of a\n' - 'class. They cannot be defined as class methods in the ' - 'actual class.\n' - 'This is consistent with the lookup of special methods that ' - 'are called\n' - 'on instances, only in this case the instance is itself a ' - 'class.\n' + 'If no "except" clause matches the exception, the search for an\n' + 'exception handler continues in the surrounding code and on the\n' \ + 'invocation stack. [1]\n' '\n' - 'See also:\n' - '\n' - ' **PEP 3119** - Introducing Abstract Base Classes\n' - ' Includes the specification for customizing ' - '"isinstance()" and\n' - ' "issubclass()" behavior through "__instancecheck__()" ' + 'If the evaluation of an expression in the header of an "except" ' \ + 'clause\n' + 'raises an exception, the original search for a handler is canceled ' \ 'and\n' - ' "__subclasscheck__()", with motivation for this ' - 'functionality in\n' - ' the context of adding Abstract Base Classes (see the ' - '"abc"\n' - ' module) to the language.\n' - '\n' - '\n' - 'Emulating callable objects\n' - '==========================\n' - '\n' - 'object.__call__(self[, args...])\n' - '\n' - ' Called when the instance is “called” as a function; if ' - 'this method\n' - ' is defined, "x(arg1, arg2, ...)" is a shorthand for\n' - ' "x.__call__(arg1, arg2, ...)".\n' - '\n' + 'a search starts for the new exception in the surrounding code and on\n' + 'the call stack (it is treated as if the entire "try" statement ' + 'raised\n' + 'the exception).\n' '\n' - 'Emulating container types\n' - '=========================\n' - '\n' - 'The following methods can be defined to implement container ' - 'objects.\n' - 'Containers usually are sequences (such as lists or tuples) ' - 'or mappings\n' - '(like dictionaries), but can represent other containers as ' - 'well. The\n' - 'first set of methods is used either to emulate a sequence or ' + 'When a matching "except" clause is found, the exception is assigned ' 'to\n' - 'emulate a mapping; the difference is that for a sequence, ' - 'the\n' - 'allowable keys should be the integers *k* for which "0 <= k ' - '< N" where\n' - '*N* is the length of the sequence, or slice objects, which ' - 'define a\n' - 'range of items. It is also recommended that mappings ' - 'provide the\n' - 'methods "keys()", "values()", "items()", "get()", ' - '"clear()",\n' - '"setdefault()", "pop()", "popitem()", "copy()", and ' - '"update()"\n' - 'behaving similar to those for Python’s standard dictionary ' - 'objects.\n' - 'The "collections" module provides a "MutableMapping" ' - 'abstract base\n' - 'class to help create those methods from a base set of ' - '"__getitem__()",\n' - '"__setitem__()", "__delitem__()", and "keys()". Mutable ' - 'sequences\n' - 'should provide methods "append()", "count()", "index()", ' - '"extend()",\n' - '"insert()", "pop()", "remove()", "reverse()" and "sort()", ' - 'like Python\n' - 'standard list objects. Finally, sequence types should ' - 'implement\n' - 'addition (meaning concatenation) and multiplication ' - '(meaning\n' - 'repetition) by defining the methods "__add__()", ' - '"__radd__()",\n' - '"__iadd__()", "__mul__()", "__rmul__()" and "__imul__()" ' - 'described\n' - 'below; they should not define other numerical operators. It ' - 'is\n' - 'recommended that both mappings and sequences implement the\n' - '"__contains__()" method to allow efficient use of the "in" ' - 'operator;\n' - 'for mappings, "in" should search the mapping’s keys; for ' - 'sequences, it\n' - 'should search through the values. It is further recommended ' - 'that both\n' - 'mappings and sequences implement the "__iter__()" method to ' - 'allow\n' - 'efficient iteration through the container; for mappings, ' - '"__iter__()"\n' - 'should be the same as "keys()"; for sequences, it should ' - 'iterate\n' - 'through the values.\n' - '\n' - 'object.__len__(self)\n' - '\n' - ' Called to implement the built-in function "len()". ' - 'Should return\n' - ' the length of the object, an integer ">=" 0. Also, an ' - 'object that\n' - ' doesn’t define a "__bool__()" method and whose ' - '"__len__()" method\n' - ' returns zero is considered to be false in a Boolean ' - 'context.\n' - '\n' - ' **CPython implementation detail:** In CPython, the length ' - 'is\n' - ' required to be at most "sys.maxsize". If the length is ' - 'larger than\n' - ' "sys.maxsize" some features (such as "len()") may raise\n' - ' "OverflowError". To prevent raising "OverflowError" by ' - 'truth value\n' - ' testing, an object must define a "__bool__()" method.\n' - '\n' - 'object.__length_hint__(self)\n' - '\n' - ' Called to implement "operator.length_hint()". Should ' - 'return an\n' - ' estimated length for the object (which may be greater or ' - 'less than\n' - ' the actual length). The length must be an integer ">=" 0. ' - 'This\n' - ' method is purely an optimization and is never required ' - 'for\n' - ' correctness.\n' - '\n' - ' New in version 3.4.\n' - '\n' - 'Note: Slicing is done exclusively with the following three ' - 'methods.\n' - ' A call like\n' - '\n' - ' a[1:2] = b\n' - '\n' - ' is translated to\n' + 'the target specified after the "as" keyword in that "except" clause,\n' + 'if present, and the "except" clause’s suite is executed. All ' + '"except"\n' + 'clauses must have an executable block. When the end of this block is\n' + 'reached, execution continues normally after the entire "try"\n' + 'statement. (This means that if two nested handlers exist for the ' + 'same\n' \ + 'exception, and the exception occurs in the "try" clause of the inner\n' + 'handler, the outer handler will not handle the exception.)\n' + '\n' + 'When an exception has been assigned using "as target", it is cleared\n' + 'at the end of the "except" clause. This is as if\n' + '\n' \ + ' except E as N:\n' + ' foo\n' + '\n' + 'was translated to\n' + '\n' \ + ' except E as N:\n' + ' try:\n' + ' foo\n' + ' finally:\n' \ + ' del N\n' + '\n' + 'This means the exception must be assigned to a different name to be\n' + 'able to refer to it after the "except" clause. Exceptions are ' + 'cleared\n' + 'because with the traceback attached to them, they form a reference\n' + 'cycle with the stack frame, keeping all locals in that frame alive\n' + 'until the next garbage collection occurs.\n' + '\n' + 'Before an "except" clause’s suite is executed, the exception is ' \ + 'stored\n' + 'in the "sys" module, where it can be accessed from within the body ' + 'of\n' + 'the "except" clause by calling "sys.exception()". When leaving an\n' + 'exception handler, the exception stored in the "sys" module is reset\n' + 'to its previous value:\n' + '\n' + ' >>> print(sys.exception())\n' \ + ' None\n' + ' >>> try:\n' + ' ... raise TypeError\n' + ' ... except:\n' + ' ... print(repr(sys.exception()))\n' + ' ... try:\n' + ' ... raise ValueError\n' + ' ... except:\n' + ' ... print(repr(sys.exception()))\n' \ + ' ... print(repr(sys.exception()))\n' \ + ' ...\n' \ + ' TypeError()\n' + ' ValueError()\n' + ' TypeError()\n' + ' >>> print(sys.exception())\n' + ' None\n' + '\n' + '\n' + '"except*" clause\n' + '================\n' + '\n' + 'The "except*" clause(s) are used for handling "ExceptionGroup"s. The\n' \ + 'exception type for matching is interpreted as in the case of ' + '"except",\n' + 'but in the case of exception groups we can have partial matches when\n' + 'the type matches some of the exceptions in the group. This means ' + 'that\n' + 'multiple "except*" clauses can execute, each handling part of the\n' + 'exception group. Each clause executes at most once and handles an\n' + 'exception group of all matching exceptions. Each exception in the\n' + 'group is handled by at most one "except*" clause, the first that\n' + 'matches it.\n' \ + '\n' + ' >>> try:\n' + ' ... raise ExceptionGroup("eg",\n' + ' ... [ValueError(1), TypeError(2), OSError(3), ' + 'OSError(4)])\n' + ' ... except* TypeError as e:\n' \ + " ... print(f'caught {type(e)} with nested {e.exceptions}')\n" + ' ... except* OSError as e:\n' + " ... print(f'caught {type(e)} with nested {e.exceptions}')\n" + ' ...\n' + " caught with nested (TypeError(2),)\n" + " caught with nested (OSError(3), " + 'OSError(4))\n' \ + ' + Exception Group Traceback (most recent call last):\n' + ' | File "", line 2, in \n' + ' | ExceptionGroup: eg\n' + ' +-+---------------- 1 ----------------\n' + ' | ValueError: 1\n' + ' +------------------------------------\n' + '\n' + 'Any remaining exceptions that were not handled by any "except*" ' + 'clause\n' + 'are re-raised at the end, along with all exceptions that were raised\n' + 'from within the "except*" clauses. If this list contains more than ' + 'one\n' \ + 'exception to reraise, they are combined into an exception group.\n' + '\n' + 'If the raised exception is not an exception group and its type ' \ + 'matches\n' + 'one of the "except*" clauses, it is caught and wrapped by an ' + 'exception\n' + 'group with an empty message string.\n' + '\n' \ + ' >>> try:\n' + ' ... raise BlockingIOError\n' + ' ... except* BlockingIOError as e:\n' + ' ... print(repr(e))\n' + ' ...\n' + " ExceptionGroup('', (BlockingIOError()))\n" '\n' - ' a[slice(1, 2, None)] = b\n' + 'An "except*" clause must have a matching expression; it cannot be\n' \ + '"except*:". Furthermore, this expression cannot contain exception\n' + 'group types, because that would have ambiguous semantics.\n' '\n' - ' and so forth. Missing slice items are always filled in ' - 'with "None".\n' + 'It is not possible to mix "except" and "except*" in the same "try".\n' + '"break", "continue" and "return" cannot appear in an "except*" ' + 'clause.\n' \ '\n' - 'object.__getitem__(self, key)\n' '\n' - ' Called to implement evaluation of "self[key]". For ' - 'sequence types,\n' - ' the accepted keys should be integers and slice objects. ' - 'Note that\n' - ' the special interpretation of negative indexes (if the ' - 'class wishes\n' - ' to emulate a sequence type) is up to the "__getitem__()" ' - 'method. If\n' - ' *key* is of an inappropriate type, "TypeError" may be ' - 'raised; if of\n' - ' a value outside the set of indexes for the sequence ' - '(after any\n' - ' special interpretation of negative values), "IndexError" ' - 'should be\n' - ' raised. For mapping types, if *key* is missing (not in ' - 'the\n' - ' container), "KeyError" should be raised.\n' + '"else" clause\n' + '=============\n' '\n' - ' Note: "for" loops expect that an "IndexError" will be ' - 'raised for\n' - ' illegal indexes to allow proper detection of the end of ' + 'The optional "else" clause is executed if the control flow leaves ' 'the\n' - ' sequence.\n' - '\n' - 'object.__setitem__(self, key, value)\n' - '\n' - ' Called to implement assignment to "self[key]". Same note ' - 'as for\n' - ' "__getitem__()". This should only be implemented for ' - 'mappings if\n' - ' the objects support changes to the values for keys, or if ' - 'new keys\n' - ' can be added, or for sequences if elements can be ' - 'replaced. The\n' - ' same exceptions should be raised for improper *key* ' - 'values as for\n' - ' the "__getitem__()" method.\n' - '\n' - 'object.__delitem__(self, key)\n' - '\n' - ' Called to implement deletion of "self[key]". Same note ' - 'as for\n' - ' "__getitem__()". This should only be implemented for ' - 'mappings if\n' - ' the objects support removal of keys, or for sequences if ' - 'elements\n' - ' can be removed from the sequence. The same exceptions ' - 'should be\n' - ' raised for improper *key* values as for the ' - '"__getitem__()" method.\n' - '\n' - 'object.__missing__(self, key)\n' - '\n' - ' Called by "dict"."__getitem__()" to implement "self[key]" ' - 'for dict\n' - ' subclasses when key is not in the dictionary.\n' - '\n' - 'object.__iter__(self)\n' - '\n' - ' This method is called when an iterator is required for a ' - 'container.\n' - ' This method should return a new iterator object that can ' - 'iterate\n' - ' over all the objects in the container. For mappings, it ' - 'should\n' - ' iterate over the keys of the container.\n' - '\n' - ' Iterator objects also need to implement this method; they ' - 'are\n' - ' required to return themselves. For more information on ' - 'iterator\n' - ' objects, see Iterator Types.\n' + '"try" suite, no exception was raised, and no "return", "continue", ' + 'or\n' + '"break" statement was executed. Exceptions in the "else" clause are\n' + 'not handled by the preceding "except" clauses.\n' '\n' - 'object.__reversed__(self)\n' '\n' - ' Called (if present) by the "reversed()" built-in to ' - 'implement\n' - ' reverse iteration. It should return a new iterator ' - 'object that\n' - ' iterates over all the objects in the container in reverse ' - 'order.\n' + '"finally" clause\n' + '================\n' \ '\n' - ' If the "__reversed__()" method is not provided, the ' - '"reversed()"\n' - ' built-in will fall back to using the sequence protocol ' - '("__len__()"\n' - ' and "__getitem__()"). Objects that support the sequence ' - 'protocol\n' - ' should only provide "__reversed__()" if they can provide ' + 'If "finally" is present, it specifies a ‘cleanup’ handler. The ' + '"try"\n' \ + 'clause is executed, including any "except" and "else" clauses. If ' 'an\n' - ' implementation that is more efficient than the one ' - 'provided by\n' - ' "reversed()".\n' - '\n' - 'The membership test operators ("in" and "not in") are ' - 'normally\n' - 'implemented as an iteration through a sequence. However, ' - 'container\n' - 'objects can supply the following special method with a more ' - 'efficient\n' - 'implementation, which also does not require the object be a ' - 'sequence.\n' - '\n' - 'object.__contains__(self, item)\n' - '\n' - ' Called to implement membership test operators. Should ' - 'return true\n' - ' if *item* is in *self*, false otherwise. For mapping ' - 'objects, this\n' - ' should consider the keys of the mapping rather than the ' - 'values or\n' - ' the key-item pairs.\n' - '\n' - ' For objects that don’t define "__contains__()", the ' - 'membership test\n' - ' first tries iteration via "__iter__()", then the old ' - 'sequence\n' - ' iteration protocol via "__getitem__()", see this section ' - 'in the\n' - ' language reference.\n' - '\n' - '\n' - 'Emulating numeric types\n' - '=======================\n' - '\n' - 'The following methods can be defined to emulate numeric ' - 'objects.\n' - 'Methods corresponding to operations that are not supported ' - 'by the\n' - 'particular kind of number implemented (e.g., bitwise ' - 'operations for\n' - 'non-integral numbers) should be left undefined.\n' - '\n' - 'object.__add__(self, other)\n' - 'object.__sub__(self, other)\n' - 'object.__mul__(self, other)\n' - 'object.__matmul__(self, other)\n' - 'object.__truediv__(self, other)\n' - 'object.__floordiv__(self, other)\n' - 'object.__mod__(self, other)\n' - 'object.__divmod__(self, other)\n' - 'object.__pow__(self, other[, modulo])\n' - 'object.__lshift__(self, other)\n' - 'object.__rshift__(self, other)\n' - 'object.__and__(self, other)\n' - 'object.__xor__(self, other)\n' - 'object.__or__(self, other)\n' - '\n' - ' These methods are called to implement the binary ' - 'arithmetic\n' - ' operations ("+", "-", "*", "@", "/", "//", "%", ' - '"divmod()",\n' - ' "pow()", "**", "<<", ">>", "&", "^", "|"). For instance, ' - 'to\n' - ' evaluate the expression "x + y", where *x* is an instance ' - 'of a\n' - ' class that has an "__add__()" method, "x.__add__(y)" is ' - 'called.\n' - ' The "__divmod__()" method should be the equivalent to ' - 'using\n' - ' "__floordiv__()" and "__mod__()"; it should not be ' - 'related to\n' - ' "__truediv__()". Note that "__pow__()" should be defined ' - 'to accept\n' - ' an optional third argument if the ternary version of the ' - 'built-in\n' - ' "pow()" function is to be supported.\n' - '\n' - ' If one of those methods does not support the operation ' - 'with the\n' - ' supplied arguments, it should return "NotImplemented".\n' - '\n' - 'object.__radd__(self, other)\n' - 'object.__rsub__(self, other)\n' - 'object.__rmul__(self, other)\n' - 'object.__rmatmul__(self, other)\n' - 'object.__rtruediv__(self, other)\n' - 'object.__rfloordiv__(self, other)\n' - 'object.__rmod__(self, other)\n' - 'object.__rdivmod__(self, other)\n' - 'object.__rpow__(self, other)\n' - 'object.__rlshift__(self, other)\n' - 'object.__rrshift__(self, other)\n' - 'object.__rand__(self, other)\n' - 'object.__rxor__(self, other)\n' - 'object.__ror__(self, other)\n' - '\n' - ' These methods are called to implement the binary ' - 'arithmetic\n' - ' operations ("+", "-", "*", "@", "/", "//", "%", ' - '"divmod()",\n' - ' "pow()", "**", "<<", ">>", "&", "^", "|") with reflected ' - '(swapped)\n' - ' operands. These functions are only called if the left ' - 'operand does\n' - ' not support the corresponding operation [3] and the ' - 'operands are of\n' - ' different types. [4] For instance, to evaluate the ' - 'expression "x -\n' - ' y", where *y* is an instance of a class that has an ' - '"__rsub__()"\n' - ' method, "y.__rsub__(x)" is called if "x.__sub__(y)" ' - 'returns\n' - ' *NotImplemented*.\n' - '\n' - ' Note that ternary "pow()" will not try calling ' - '"__rpow__()" (the\n' - ' coercion rules would become too complicated).\n' - '\n' - ' Note: If the right operand’s type is a subclass of the ' - 'left\n' - ' operand’s type and that subclass provides the reflected ' - 'method\n' - ' for the operation, this method will be called before ' - 'the left\n' - ' operand’s non-reflected method. This behavior allows ' - 'subclasses\n' - ' to override their ancestors’ operations.\n' - '\n' - 'object.__iadd__(self, other)\n' - 'object.__isub__(self, other)\n' - 'object.__imul__(self, other)\n' - 'object.__imatmul__(self, other)\n' - 'object.__itruediv__(self, other)\n' - 'object.__ifloordiv__(self, other)\n' - 'object.__imod__(self, other)\n' - 'object.__ipow__(self, other[, modulo])\n' - 'object.__ilshift__(self, other)\n' - 'object.__irshift__(self, other)\n' - 'object.__iand__(self, other)\n' - 'object.__ixor__(self, other)\n' - 'object.__ior__(self, other)\n' - '\n' - ' These methods are called to implement the augmented ' - 'arithmetic\n' - ' assignments ("+=", "-=", "*=", "@=", "/=", "//=", "%=", ' - '"**=",\n' - ' "<<=", ">>=", "&=", "^=", "|="). These methods should ' - 'attempt to\n' - ' do the operation in-place (modifying *self*) and return ' - 'the result\n' - ' (which could be, but does not have to be, *self*). If a ' - 'specific\n' - ' method is not defined, the augmented assignment falls ' - 'back to the\n' - ' normal methods. For instance, if *x* is an instance of a ' - 'class\n' - ' with an "__iadd__()" method, "x += y" is equivalent to "x ' - '=\n' - ' x.__iadd__(y)" . Otherwise, "x.__add__(y)" and ' - '"y.__radd__(x)" are\n' - ' considered, as with the evaluation of "x + y". In ' - 'certain\n' - ' situations, augmented assignment can result in unexpected ' - 'errors\n' - ' (see Why does a_tuple[i] += [‘item’] raise an exception ' - 'when the\n' - ' addition works?), but this behavior is in fact part of ' - 'the data\n' - ' model.\n' - '\n' - 'object.__neg__(self)\n' - 'object.__pos__(self)\n' - 'object.__abs__(self)\n' - 'object.__invert__(self)\n' - '\n' - ' Called to implement the unary arithmetic operations ("-", ' - '"+",\n' - ' "abs()" and "~").\n' - '\n' - 'object.__complex__(self)\n' - 'object.__int__(self)\n' - 'object.__float__(self)\n' - '\n' - ' Called to implement the built-in functions "complex()", ' - '"int()" and\n' - ' "float()". Should return a value of the appropriate ' - 'type.\n' - '\n' - 'object.__index__(self)\n' - '\n' - ' Called to implement "operator.index()", and whenever ' - 'Python needs\n' - ' to losslessly convert the numeric object to an integer ' - 'object (such\n' - ' as in slicing, or in the built-in "bin()", "hex()" and ' - '"oct()"\n' - ' functions). Presence of this method indicates that the ' - 'numeric\n' - ' object is an integer type. Must return an integer.\n' - '\n' - ' Note: In order to have a coherent integer type class, ' - 'when\n' - ' "__index__()" is defined "__int__()" should also be ' - 'defined, and\n' - ' both should return the same value.\n' - '\n' - 'object.__round__(self[, ndigits])\n' - 'object.__trunc__(self)\n' - 'object.__floor__(self)\n' - 'object.__ceil__(self)\n' - '\n' - ' Called to implement the built-in function "round()" and ' - '"math"\n' - ' functions "trunc()", "floor()" and "ceil()". Unless ' - '*ndigits* is\n' - ' passed to "__round__()" all these methods should return ' - 'the value\n' - ' of the object truncated to an "Integral" (typically an ' - '"int").\n' - '\n' - ' If "__int__()" is not defined then the built-in function ' - '"int()"\n' - ' falls back to "__trunc__()".\n' - '\n' - '\n' - 'With Statement Context Managers\n' - '===============================\n' - '\n' - 'A *context manager* is an object that defines the runtime ' - 'context to\n' - 'be established when executing a "with" statement. The ' - 'context manager\n' - 'handles the entry into, and the exit from, the desired ' - 'runtime context\n' - 'for the execution of the block of code. Context managers ' - 'are normally\n' - 'invoked using the "with" statement (described in section The ' - 'with\n' - 'statement), but can also be used by directly invoking their ' - 'methods.\n' - '\n' - 'Typical uses of context managers include saving and ' - 'restoring various\n' - 'kinds of global state, locking and unlocking resources, ' - 'closing opened\n' - 'files, etc.\n' - '\n' - 'For more information on context managers, see Context ' - 'Manager Types.\n' - '\n' - 'object.__enter__(self)\n' - '\n' - ' Enter the runtime context related to this object. The ' - '"with"\n' - ' statement will bind this method’s return value to the ' - 'target(s)\n' - ' specified in the "as" clause of the statement, if any.\n' - '\n' - 'object.__exit__(self, exc_type, exc_value, traceback)\n' - '\n' - ' Exit the runtime context related to this object. The ' - 'parameters\n' - ' describe the exception that caused the context to be ' - 'exited. If the\n' - ' context was exited without an exception, all three ' - 'arguments will\n' - ' be "None".\n' - '\n' - ' If an exception is supplied, and the method wishes to ' - 'suppress the\n' - ' exception (i.e., prevent it from being propagated), it ' - 'should\n' - ' return a true value. Otherwise, the exception will be ' - 'processed\n' - ' normally upon exit from this method.\n' - '\n' - ' Note that "__exit__()" methods should not reraise the ' - 'passed-in\n' - ' exception; this is the caller’s responsibility.\n' - '\n' - 'See also:\n' - '\n' - ' **PEP 343** - The “with” statement\n' - ' The specification, background, and examples for the ' - 'Python "with"\n' - ' statement.\n' - '\n' - '\n' - 'Special method lookup\n' - '=====================\n' - '\n' - 'For custom classes, implicit invocations of special methods ' - 'are only\n' - 'guaranteed to work correctly if defined on an object’s type, ' - 'not in\n' - 'the object’s instance dictionary. That behaviour is the ' - 'reason why\n' - 'the following code raises an exception:\n' - '\n' - ' >>> class C:\n' - ' ... pass\n' + 'exception occurs in any of the clauses and is not handled, the\n' + 'exception is temporarily saved. The "finally" clause is executed. ' + 'If\n' + 'there is a saved exception it is re-raised at the end of the ' + '"finally"\n' \ + 'clause. If the "finally" clause raises another exception, the saved\n' + 'exception is set as the context of the new exception. If the ' + '"finally"\n' + 'clause executes a "return", "break" or "continue" statement, the ' + 'saved\n' + 'exception is discarded:\n' + '\n' \ + ' >>> def f():\n' + ' ... try:\n' + ' ... 1/0\n' + ' ... finally:\n' + ' ... return 42\n' \ ' ...\n' - ' >>> c = C()\n' - ' >>> c.__len__ = lambda: 5\n' - ' >>> len(c)\n' - ' Traceback (most recent call last):\n' - ' File "", line 1, in \n' - " TypeError: object of type 'C' has no len()\n" - '\n' - 'The rationale behind this behaviour lies with a number of ' - 'special\n' - 'methods such as "__hash__()" and "__repr__()" that are ' - 'implemented by\n' - 'all objects, including type objects. If the implicit lookup ' - 'of these\n' - 'methods used the conventional lookup process, they would ' - 'fail when\n' - 'invoked on the type object itself:\n' + ' >>> f()\n' \ + ' 42\n' '\n' - ' >>> 1 .__hash__() == hash(1)\n' - ' True\n' - ' >>> int.__hash__() == hash(int)\n' - ' Traceback (most recent call last):\n' - ' File "", line 1, in \n' - " TypeError: descriptor '__hash__' of 'int' object needs an " - 'argument\n' + 'The exception information is not available to the program during\n' + 'execution of the "finally" clause.\n' '\n' - 'Incorrectly attempting to invoke an unbound method of a ' - 'class in this\n' - 'way is sometimes referred to as ‘metaclass confusion’, and ' - 'is avoided\n' - 'by bypassing the instance when looking up special methods:\n' + 'When a "return", "break" or "continue" statement is executed in the\n' + '"try" suite of a "try"…"finally" statement, the "finally" clause is\n' \ + 'also executed ‘on the way out.’\n' '\n' - ' >>> type(1).__hash__(1) == hash(1)\n' - ' True\n' - ' >>> type(int).__hash__(int) == hash(int)\n' - ' True\n' - '\n' - 'In addition to bypassing any instance attributes in the ' - 'interest of\n' - 'correctness, implicit special method lookup generally also ' - 'bypasses\n' - 'the "__getattribute__()" method even of the object’s ' - 'metaclass:\n' + 'The return value of a function is determined by the last "return"\n' + 'statement executed. Since the "finally" clause always executes, a\n' + '"return" statement executed in the "finally" clause will always be ' + 'the\n' + 'last one executed:\n' '\n' - ' >>> class Meta(type):\n' - ' ... def __getattribute__(*args):\n' - ' ... print("Metaclass getattribute invoked")\n' - ' ... return type.__getattribute__(*args)\n' + ' >>> def foo():\n' + ' ... try:\n' + " ... return 'try'\n" + ' ... finally:\n' + " ... return 'finally'\n" ' ...\n' - ' >>> class C(object, metaclass=Meta):\n' - ' ... def __len__(self):\n' - ' ... return 10\n' - ' ... def __getattribute__(*args):\n' - ' ... print("Class getattribute invoked")\n' - ' ... return object.__getattribute__(*args)\n' - ' ...\n' - ' >>> c = C()\n' - ' >>> c.__len__() # Explicit lookup via ' - 'instance\n' - ' Class getattribute invoked\n' - ' 10\n' - ' >>> type(c).__len__(c) # Explicit lookup via ' - 'type\n' - ' Metaclass getattribute invoked\n' - ' 10\n' - ' >>> len(c) # Implicit lookup\n' - ' 10\n' - '\n' - 'Bypassing the "__getattribute__()" machinery in this fashion ' - 'provides\n' - 'significant scope for speed optimisations within the ' - 'interpreter, at\n' - 'the cost of some flexibility in the handling of special ' - 'methods (the\n' - 'special method *must* be set on the class object itself in ' - 'order to be\n' - 'consistently invoked by the interpreter).\n', - 'string-methods': 'String Methods\n' - '**************\n' - '\n' - 'Strings implement all of the common sequence operations, ' - 'along with\n' - 'the additional methods described below.\n' - '\n' - 'Strings also support two styles of string formatting, one ' - 'providing a\n' - 'large degree of flexibility and customization (see ' - '"str.format()",\n' - 'Format String Syntax and Custom String Formatting) and the ' - 'other based\n' - 'on C "printf" style formatting that handles a narrower ' - 'range of types\n' - 'and is slightly harder to use correctly, but is often ' - 'faster for the\n' - 'cases it can handle (printf-style String Formatting).\n' - '\n' - 'The Text Processing Services section of the standard ' - 'library covers a\n' - 'number of other modules that provide various text related ' - 'utilities\n' - '(including regular expression support in the "re" ' - 'module).\n' - '\n' - 'str.capitalize()\n' - '\n' - ' Return a copy of the string with its first character ' - 'capitalized\n' - ' and the rest lowercased.\n' - '\n' - 'str.casefold()\n' - '\n' - ' Return a casefolded copy of the string. Casefolded ' - 'strings may be\n' - ' used for caseless matching.\n' - '\n' - ' Casefolding is similar to lowercasing but more ' - 'aggressive because\n' - ' it is intended to remove all case distinctions in a ' - 'string. For\n' - ' example, the German lowercase letter "\'ß\'" is ' - 'equivalent to ""ss"".\n' - ' Since it is already lowercase, "lower()" would do ' - 'nothing to "\'ß\'";\n' - ' "casefold()" converts it to ""ss"".\n' - '\n' - ' The casefolding algorithm is described in section 3.13 ' - 'of the\n' - ' Unicode Standard.\n' - '\n' - ' New in version 3.3.\n' - '\n' - 'str.center(width[, fillchar])\n' - '\n' - ' Return centered in a string of length *width*. Padding ' - 'is done\n' - ' using the specified *fillchar* (default is an ASCII ' - 'space). The\n' - ' original string is returned if *width* is less than or ' - 'equal to\n' - ' "len(s)".\n' - '\n' - 'str.count(sub[, start[, end]])\n' - '\n' - ' Return the number of non-overlapping occurrences of ' - 'substring *sub*\n' - ' in the range [*start*, *end*]. Optional arguments ' - '*start* and\n' - ' *end* are interpreted as in slice notation.\n' - '\n' - 'str.encode(encoding="utf-8", errors="strict")\n' - '\n' - ' Return an encoded version of the string as a bytes ' - 'object. Default\n' - ' encoding is "\'utf-8\'". *errors* may be given to set a ' - 'different\n' - ' error handling scheme. The default for *errors* is ' - '"\'strict\'",\n' - ' meaning that encoding errors raise a "UnicodeError". ' - 'Other possible\n' - ' values are "\'ignore\'", "\'replace\'", ' - '"\'xmlcharrefreplace\'",\n' - ' "\'backslashreplace\'" and any other name registered ' - 'via\n' - ' "codecs.register_error()", see section Error Handlers. ' - 'For a list\n' - ' of possible encodings, see section Standard Encodings.\n' - '\n' - ' Changed in version 3.1: Support for keyword arguments ' - 'added.\n' - '\n' - 'str.endswith(suffix[, start[, end]])\n' - '\n' - ' Return "True" if the string ends with the specified ' - '*suffix*,\n' - ' otherwise return "False". *suffix* can also be a tuple ' - 'of suffixes\n' - ' to look for. With optional *start*, test beginning at ' - 'that\n' - ' position. With optional *end*, stop comparing at that ' - 'position.\n' - '\n' - 'str.expandtabs(tabsize=8)\n' - '\n' - ' Return a copy of the string where all tab characters ' - 'are replaced\n' - ' by one or more spaces, depending on the current column ' - 'and the\n' - ' given tab size. Tab positions occur every *tabsize* ' - 'characters\n' - ' (default is 8, giving tab positions at columns 0, 8, 16 ' - 'and so on).\n' - ' To expand the string, the current column is set to zero ' - 'and the\n' - ' string is examined character by character. If the ' - 'character is a\n' - ' tab ("\\t"), one or more space characters are inserted ' - 'in the result\n' - ' until the current column is equal to the next tab ' - 'position. (The\n' - ' tab character itself is not copied.) If the character ' - 'is a newline\n' - ' ("\\n") or return ("\\r"), it is copied and the current ' - 'column is\n' - ' reset to zero. Any other character is copied unchanged ' - 'and the\n' - ' current column is incremented by one regardless of how ' + ' >>> foo()\n' + " 'finally'\n" + '\n' + 'Changed in version 3.8: Prior to Python 3.8, a "continue" statement\n' + 'was illegal in the "finally" clause due to a problem with the\n' + 'implementation.\n', + 'types': 'The standard type hierarchy\n' \ + '***************************\n' + '\n' \ + 'Below is a list of the types that are built into Python. ' + 'Extension\n' + 'modules (written in C, Java, or other languages, depending on the\n' + 'implementation) can define additional types. Future versions of\n' \ + 'Python may add types to the type hierarchy (e.g., rational ' + 'numbers,\n' + 'efficiently stored arrays of integers, etc.), although such ' + 'additions\n' + 'will often be provided via the standard library instead.\n' + '\n' + 'Some of the type descriptions below contain a paragraph listing\n' \ + '‘special attributes.’ These are attributes that provide access to ' + 'the\n' \ + 'implementation and are not intended for general use. Their ' \ + 'definition\n' \ + 'may change in the future.\n' + '\n' + '\n' + 'None\n' + '====\n' \ + '\n' + 'This type has a single value. There is a single object with this\n' + 'value. This object is accessed through the built-in name "None". It ' + 'is\n' \ + 'used to signify the absence of a value in many situations, e.g., it ' + 'is\n' + 'returned from functions that don’t explicitly return anything. Its\n' + 'truth value is false.\n' + '\n' + '\n' \ + 'NotImplemented\n' + '==============\n' + '\n' + 'This type has a single value. There is a single object with this\n' + 'value. This object is accessed through the built-in name\n' \ + '"NotImplemented". Numeric methods and rich comparison methods ' + 'should\n' + 'return this value if they do not implement the operation for the\n' + 'operands provided. (The interpreter will then try the reflected\n' + 'operation, or some other fallback, depending on the operator.) It\n' + 'should not be evaluated in a boolean context.\n' + '\n' + 'See Implementing the arithmetic operations for more details.\n' + '\n' + 'Changed in version 3.9: Evaluating "NotImplemented" in a boolean\n' + 'context is deprecated. While it currently evaluates as true, it ' + 'will\n' + 'emit a "DeprecationWarning". It will raise a "TypeError" in a ' + 'future\n' + 'version of Python.\n' + '\n' + '\n' + 'Ellipsis\n' + '========\n' + '\n' + 'This type has a single value. There is a single object with this\n' + 'value. This object is accessed through the literal "..." or the ' + 'built-\n' + 'in name "Ellipsis". Its truth value is true.\n' + '\n' + '\n' \ + '"numbers.Number"\n' + '================\n' + '\n' \ + 'These are created by numeric literals and returned as results by\n' + 'arithmetic operators and arithmetic built-in functions. Numeric\n' + 'objects are immutable; once created their value never changes. ' \ + 'Python\n' + 'numbers are of course strongly related to mathematical numbers, ' + 'but\n' \ + 'subject to the limitations of numerical representation in ' + 'computers.\n' + '\n' + 'The string representations of the numeric classes, computed by\n' + '"__repr__()" and "__str__()", have the following properties:\n' + '\n' + '* They are valid numeric literals which, when passed to their ' + 'class\n' + ' constructor, produce an object having the value of the original\n' + ' numeric.\n' + '\n' + '* The representation is in base 10, when possible.\n' + '\n' \ + '* Leading zeros, possibly excepting a single zero before a decimal\n' + ' point, are not shown.\n' \ + '\n' + '* Trailing zeros, possibly excepting a single zero after a decimal\n' + ' point, are not shown.\n' + '\n' + '* A sign is shown only when the number is negative.\n' + '\n' \ + 'Python distinguishes between integers, floating-point numbers, and\n' + 'complex numbers:\n' + '\n' \ + '\n' + '"numbers.Integral"\n' + '------------------\n' \ + '\n' + 'These represent elements from the mathematical set of integers\n' + '(positive and negative).\n' \ + '\n' + 'Note:\n' + '\n' + ' The rules for integer representation are intended to give the ' + 'most\n' + ' meaningful interpretation of shift and mask operations involving\n' + ' negative integers.\n' + '\n' + 'There are two types of integers:\n' \ + '\n' + 'Integers ("int")\n' + ' These represent numbers in an unlimited range, subject to ' \ + 'available\n' + ' (virtual) memory only. For the purpose of shift and mask\n' + ' operations, a binary representation is assumed, and negative\n' + ' numbers are represented in a variant of 2’s complement which ' + 'gives\n' + ' the illusion of an infinite string of sign bits extending to ' + 'the\n' + ' left.\n' + '\n' + 'Booleans ("bool")\n' \ + ' These represent the truth values False and True. The two ' + 'objects\n' + ' representing the values "False" and "True" are the only Boolean\n' + ' objects. The Boolean type is a subtype of the integer type, and\n' + ' Boolean values behave like the values 0 and 1, respectively, in\n' + ' almost all contexts, the exception being that when converted to ' + 'a\n' + ' string, the strings ""False"" or ""True"" are returned,\n' + ' respectively.\n' + '\n' + '\n' \ + '"numbers.Real" ("float")\n' + '------------------------\n' + '\n' + 'These represent machine-level double precision floating-point ' \ + 'numbers.\n' + 'You are at the mercy of the underlying machine architecture (and C ' + 'or\n' \ + 'Java implementation) for the accepted range and handling of ' + 'overflow.\n' + 'Python does not support single-precision floating-point numbers; ' + 'the\n' + 'savings in processor and memory usage that are usually the reason ' \ + 'for\n' \ + 'using these are dwarfed by the overhead of using objects in Python, ' + 'so\n' + 'there is no reason to complicate the language with two kinds of\n' + 'floating-point numbers.\n' \ + '\n' + '\n' + '"numbers.Complex" ("complex")\n' + '-----------------------------\n' + '\n' + 'These represent complex numbers as a pair of machine-level double\n' \ + 'precision floating-point numbers. The same caveats apply as for\n' + 'floating-point numbers. The real and imaginary parts of a complex\n' \ + 'number "z" can be retrieved through the read-only attributes ' \ + '"z.real"\n' \ + 'and "z.imag".\n' + '\n' + '\n' + 'Sequences\n' + '=========\n' + '\n' + 'These represent finite ordered sets indexed by non-negative ' + 'numbers.\n' \ + 'The built-in function "len()" returns the number of items of a\n' + 'sequence. When the length of a sequence is *n*, the index set ' + 'contains\n' + 'the numbers 0, 1, …, *n*-1. Item *i* of sequence *a* is selected ' + 'by\n' + '"a[i]". Some sequences, including built-in sequences, interpret\n' + 'negative subscripts by adding the sequence length. For example,\n' + '"a[-2]" equals "a[n-2]", the second to last item of sequence a ' + 'with\n' + 'length "n".\n' + '\n' + 'Sequences also support slicing: "a[i:j]" selects all items with ' + 'index\n' + '*k* such that *i* "<=" *k* "<" *j*. When used as an expression, a\n' + 'slice is a sequence of the same type. The comment above about ' + 'negative\n' + 'indexes also applies to negative slice positions.\n' + '\n' + 'Some sequences also support “extended slicing” with a third “step”\n' \ + 'parameter: "a[i:j:k]" selects all items of *a* with index *x* where ' + '"x\n' + '= i + n*k", *n* ">=" "0" and *i* "<=" *x* "<" *j*.\n' \ + '\n' \ + 'Sequences are distinguished according to their mutability:\n' + '\n' + '\n' + 'Immutable sequences\n' + '-------------------\n' + '\n' + 'An object of an immutable sequence type cannot change once it is\n' + 'created. (If the object contains references to other objects, ' + 'these\n' + 'other objects may be mutable and may be changed; however, the\n' + 'collection of objects directly referenced by an immutable object\n' \ + 'cannot change.)\n' + '\n' + 'The following types are immutable sequences:\n' + '\n' \ + 'Strings\n' + ' A string is a sequence of values that represent Unicode code\n' \ + ' points. All the code points in the range "U+0000 - U+10FFFF" can ' + 'be\n' + ' represented in a string. Python doesn’t have a char type; ' \ + 'instead,\n' \ + ' every code point in the string is represented as a string ' \ + 'object\n' + ' with length "1". The built-in function "ord()" converts a code\n' + ' point from its string form to an integer in the range "0 - ' + '10FFFF";\n' + ' "chr()" converts an integer in the range "0 - 10FFFF" to the\n' + ' corresponding length "1" string object. "str.encode()" can be ' \ + 'used\n' + ' to convert a "str" to "bytes" using the given text encoding, ' + 'and\n' \ + ' "bytes.decode()" can be used to achieve the opposite.\n' + '\n' + 'Tuples\n' \ + ' The items of a tuple are arbitrary Python objects. Tuples of two ' + 'or\n' + ' more items are formed by comma-separated lists of expressions. ' + 'A\n' + ' tuple of one item (a ‘singleton’) can be formed by affixing a ' \ + 'comma\n' \ + ' to an expression (an expression by itself does not create a ' + 'tuple,\n' + ' since parentheses must be usable for grouping of expressions). ' + 'An\n' + ' empty tuple can be formed by an empty pair of parentheses.\n' + '\n' + 'Bytes\n' + ' A bytes object is an immutable array. The items are 8-bit ' \ + 'bytes,\n' \ + ' represented by integers in the range 0 <= x < 256. Bytes ' + 'literals\n' + ' (like "b\'abc\'") and the built-in "bytes()" constructor can be ' + 'used\n' + ' to create bytes objects. Also, bytes objects can be decoded to\n' + ' strings via the "decode()" method.\n' + '\n' + '\n' + 'Mutable sequences\n' + '-----------------\n' + '\n' + 'Mutable sequences can be changed after they are created. The\n' + 'subscription and slicing notations can be used as the target of\n' + 'assignment and "del" (delete) statements.\n' + '\n' + 'Note:\n' + '\n' + ' The "collections" and "array" module provide additional examples ' + 'of\n' + ' mutable sequence types.\n' + '\n' \ + 'There are currently two intrinsic mutable sequence types:\n' + '\n' + 'Lists\n' + ' The items of a list are arbitrary Python objects. Lists are ' + 'formed\n' \ + ' by placing a comma-separated list of expressions in square\n' + ' brackets. (Note that there are no special cases needed to form\n' \ + ' lists of length 0 or 1.)\n' + '\n' \ + 'Byte Arrays\n' + ' A bytearray object is a mutable array. They are created by the\n' \ + ' built-in "bytearray()" constructor. Aside from being mutable ' + '(and\n' + ' hence unhashable), byte arrays otherwise provide the same ' \ + 'interface\n' + ' and functionality as immutable "bytes" objects.\n' + '\n' + '\n' + 'Set types\n' \ + '=========\n' + '\n' + 'These represent unordered, finite sets of unique, immutable ' + 'objects.\n' + 'As such, they cannot be indexed by any subscript. However, they can ' + 'be\n' \ + 'iterated over, and the built-in function "len()" returns the number ' + 'of\n' + 'items in a set. Common uses for sets are fast membership testing,\n' + 'removing duplicates from a sequence, and computing mathematical\n' + 'operations such as intersection, union, difference, and symmetric\n' + 'difference.\n' + '\n' \ + 'For set elements, the same immutability rules apply as for ' + 'dictionary\n' + 'keys. Note that numeric types obey the normal rules for numeric\n' + 'comparison: if two numbers compare equal (e.g., "1" and "1.0"), ' + 'only\n' + 'one of them can be contained in a set.\n' \ + '\n' + 'There are currently two intrinsic set types:\n' + '\n' + 'Sets\n' + ' These represent a mutable set. They are created by the built-in\n' + ' "set()" constructor and can be modified afterwards by several\n' + ' methods, such as "add()".\n' + '\n' + 'Frozen sets\n' + ' These represent an immutable set. They are created by the ' + 'built-in\n' + ' "frozenset()" constructor. As a frozenset is immutable and\n' + ' *hashable*, it can be used again as an element of another set, ' \ + 'or\n' + ' as a dictionary key.\n' + '\n' + '\n' + 'Mappings\n' \ + '========\n' + '\n' + 'These represent finite sets of objects indexed by arbitrary index\n' \ + 'sets. The subscript notation "a[k]" selects the item indexed by ' \ + '"k"\n' \ + 'from the mapping "a"; this can be used in expressions and as the\n' + 'target of assignments or "del" statements. The built-in function\n' + '"len()" returns the number of items in a mapping.\n' + '\n' \ + 'There is currently a single intrinsic mapping type:\n' + '\n' + '\n' \ + 'Dictionaries\n' \ + '------------\n' + '\n' \ + 'These represent finite sets of objects indexed by nearly arbitrary\n' + 'values. The only types of values not acceptable as keys are ' + 'values\n' + 'containing lists or dictionaries or other mutable types that are\n' + 'compared by value rather than by object identity, the reason being\n' + 'that the efficient implementation of dictionaries requires a key’s\n' + 'hash value to remain constant. Numeric types used for keys obey ' + 'the\n' + 'normal rules for numeric comparison: if two numbers compare equal\n' \ + '(e.g., "1" and "1.0") then they can be used interchangeably to ' + 'index\n' + 'the same dictionary entry.\n' + '\n' + 'Dictionaries preserve insertion order, meaning that keys will be\n' + 'produced in the same order they were added sequentially over the\n' + 'dictionary. Replacing an existing key does not change the order,\n' \ + 'however removing a key and re-inserting it will add it to the end\n' + 'instead of keeping its old place.\n' + '\n' + 'Dictionaries are mutable; they can be created by the "{}" notation\n' + '(see section Dictionary displays).\n' + '\n' + 'The extension modules "dbm.ndbm" and "dbm.gnu" provide additional\n' + 'examples of mapping types, as does the "collections" module.\n' \ + '\n' + 'Changed in version 3.7: Dictionaries did not preserve insertion ' + 'order\n' \ + 'in versions of Python before 3.6. In CPython 3.6, insertion order ' \ + 'was\n' + 'preserved, but it was considered an implementation detail at that ' + 'time\n' + 'rather than a language guarantee.\n' + '\n' + '\n' + 'Callable types\n' + '==============\n' + '\n' \ + 'These are the types to which the function call operation (see ' + 'section\n' + 'Calls) can be applied:\n' + '\n' + '\n' + 'User-defined functions\n' + '----------------------\n' + '\n' \ + 'A user-defined function object is created by a function definition\n' \ + '(see section Function definitions). It should be called with an\n' + 'argument list containing the same number of items as the ' + 'function’s\n' + 'formal parameter list.\n' + '\n' + '\n' + 'Special read-only attributes\n' + '~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n' \ + '\n' \ + '+----------------------------------------------------+----------------------------------------------------+\n' + '| Attribute | ' + 'Meaning |\n' + '|====================================================|====================================================|\n' \ + '| function.__globals__ | A reference ' \ + 'to the "dictionary" that holds the |\n' \ + '| | function’s ' + 'global variables – the global namespace |\n' + '| | of the ' + 'module in which the function was defined. |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' \ + '| function.__closure__ | "None" or a ' + '"tuple" of cells that contain bindings |\n' + '| | for the ' + 'function’s free variables. A cell object |\n' + '| | has the ' + 'attribute "cell_contents". This can be |\n' + '| | used to get ' + 'the value of the cell, as well as set |\n' + '| | the ' + 'value. |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '\n' + '\n' \ + 'Special writable attributes\n' + '~~~~~~~~~~~~~~~~~~~~~~~~~~~\n' + '\n' \ + 'Most of these attributes check the type of the assigned value:\n' + '\n' \ + '+----------------------------------------------------+----------------------------------------------------+\n' + '| Attribute | ' + 'Meaning |\n' + '|====================================================|====================================================|\n' + '| function.__doc__ | The ' + 'function’s documentation string, or "None" if |\n' \ + '| | ' + 'unavailable. |\n' \ + '+----------------------------------------------------+----------------------------------------------------+\n' + '| function.__name__ | The ' + 'function’s name. See also: "__name__ |\n' + '| | ' + 'attributes". |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '| function.__qualname__ | The ' + 'function’s *qualified name*. See also: |\n' + '| | ' + '"__qualname__ attributes". Added in version 3.3. |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '| function.__module__ | The name of ' + 'the module the function was defined |\n' + '| | in, or ' + '"None" if unavailable. |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '| function.__defaults__ | A "tuple" ' \ + 'containing default *parameter* values |\n' + '| | for those ' \ + 'parameters that have defaults, or "None" |\n' + '| | if no ' + 'parameters have a default value. |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '| function.__code__ | The code ' + 'object representing the compiled function |\n' + '| | ' \ + 'body. |\n' \ + '+----------------------------------------------------+----------------------------------------------------+\n' + '| function.__dict__ | The ' + 'namespace supporting arbitrary function |\n' + '| | attributes. ' + 'See also: "__dict__ attributes". |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' \ + '| function.__annotations__ | A ' + '"dictionary" containing annotations of |\n' \ + '| | ' + '*parameters*. The keys of the dictionary are the |\n' + '| | parameter ' + 'names, and "\'return\'" for the return |\n' + '| | annotation, ' + 'if provided. See also: Annotations |\n' + '| | Best ' + 'Practices. |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '| function.__kwdefaults__ | A ' + '"dictionary" containing defaults for keyword- |\n' + '| | only ' \ + '*parameters*. |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '| function.__type_params__ | A "tuple" ' + 'containing the type parameters of a |\n' + '| | generic ' + 'function. Added in version 3.12. |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '\n' \ + 'Function objects also support getting and setting arbitrary\n' + 'attributes, which can be used, for example, to attach metadata to\n' + 'functions. Regular attribute dot-notation is used to get and set ' \ + 'such\n' + 'attributes.\n' + '\n' + '**CPython implementation detail:** CPython’s current ' + 'implementation\n' + 'only supports function attributes on user-defined functions. ' + 'Function\n' + 'attributes on built-in functions may be supported in the future.\n' + '\n' + 'Additional information about a function’s definition can be ' \ + 'retrieved\n' + 'from its code object (accessible via the "__code__" attribute).\n' + '\n' + '\n' \ + 'Instance methods\n' + '----------------\n' + '\n' + 'An instance method object combines a class, a class instance and ' + 'any\n' + 'callable object (normally a user-defined function).\n' + '\n' \ + 'Special read-only attributes:\n' + '\n' \ + '+----------------------------------------------------+----------------------------------------------------+\n' + '| method.__self__ | Refers to ' + 'the class instance object to which the |\n' + '| | method is ' + 'bound |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '| method.__func__ | Refers to ' + 'the original function object |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '| method.__doc__ | The method’s ' + 'documentation (same as |\n' \ + '| | ' + '"method.__func__.__doc__"). A "string" if the |\n' + '| | original ' \ + 'function had a docstring, else "None". |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' \ + '| method.__name__ | The name of ' + 'the method (same as |\n' \ + '| | ' + '"method.__func__.__name__") |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '| method.__module__ | The name of ' \ + 'the module the method was defined in, |\n' + '| | or "None" if ' + 'unavailable. |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '\n' + 'Methods also support accessing (but not setting) the arbitrary\n' \ + 'function attributes on the underlying function object.\n' + '\n' + 'User-defined method objects may be created when getting an ' + 'attribute\n' + 'of a class (perhaps via an instance of that class), if that ' + 'attribute\n' + 'is a user-defined function object or a "classmethod" object.\n' + '\n' + 'When an instance method object is created by retrieving a ' \ + 'user-defined\n' \ + 'function object from a class via one of its instances, its ' + '"__self__"\n' + 'attribute is the instance, and the method object is said to be\n' + '*bound*. The new method’s "__func__" attribute is the original\n' + 'function object.\n' + '\n' + 'When an instance method object is created by retrieving a\n' + '"classmethod" object from a class or instance, its "__self__"\n' \ + 'attribute is the class itself, and its "__func__" attribute is the\n' + 'function object underlying the class method.\n' \ + '\n' + 'When an instance method object is called, the underlying function\n' + '("__func__") is called, inserting the class instance ("__self__") ' \ + 'in\n' + 'front of the argument list. For instance, when "C" is a class ' + 'which\n' \ + 'contains a definition for a function "f()", and "x" is an instance ' + 'of\n' + '"C", calling "x.f(1)" is equivalent to calling "C.f(x, 1)".\n' + '\n' + 'When an instance method object is derived from a "classmethod" ' + 'object,\n' + 'the “class instance” stored in "__self__" will actually be the ' + 'class\n' + 'itself, so that calling either "x.f(1)" or "C.f(1)" is equivalent ' + 'to\n' + 'calling "f(C,1)" where "f" is the underlying function.\n' \ + '\n' + 'It is important to note that user-defined functions which are\n' + 'attributes of a class instance are not converted to bound methods;\n' + 'this *only* happens when the function is an attribute of the ' + 'class.\n' \ + '\n' \ + '\n' + 'Generator functions\n' + '-------------------\n' + '\n' + 'A function or method which uses the "yield" statement (see section ' + 'The\n' \ + 'yield statement) is called a *generator function*. Such a ' + 'function,\n' + 'when called, always returns an *iterator* object which can be used ' + 'to\n' + 'execute the body of the function: calling the iterator’s\n' + '"iterator.__next__()" method will cause the function to execute ' + 'until\n' \ + 'it provides a value using the "yield" statement. When the ' + 'function\n' \ + 'executes a "return" statement or falls off the end, a ' + '"StopIteration"\n' + 'exception is raised and the iterator will have reached the end of ' 'the\n' - ' character is represented when printed.\n' - '\n' - " >>> '01\\t012\\t0123\\t01234'.expandtabs()\n" - " '01 012 0123 01234'\n" - " >>> '01\\t012\\t0123\\t01234'.expandtabs(4)\n" - " '01 012 0123 01234'\n" - '\n' - 'str.find(sub[, start[, end]])\n' - '\n' - ' Return the lowest index in the string where substring ' - '*sub* is\n' - ' found within the slice "s[start:end]". Optional ' - 'arguments *start*\n' - ' and *end* are interpreted as in slice notation. Return ' - '"-1" if\n' - ' *sub* is not found.\n' - '\n' - ' Note: The "find()" method should be used only if you ' - 'need to know\n' - ' the position of *sub*. To check if *sub* is a ' - 'substring or not,\n' - ' use the "in" operator:\n' - '\n' - " >>> 'Py' in 'Python'\n" - ' True\n' - '\n' - 'str.format(*args, **kwargs)\n' - '\n' - ' Perform a string formatting operation. The string on ' - 'which this\n' - ' method is called can contain literal text or ' - 'replacement fields\n' - ' delimited by braces "{}". Each replacement field ' - 'contains either\n' - ' the numeric index of a positional argument, or the name ' - 'of a\n' - ' keyword argument. Returns a copy of the string where ' - 'each\n' - ' replacement field is replaced with the string value of ' + 'set of values to be returned.\n' + '\n' + '\n' + 'Coroutine functions\n' \ + '-------------------\n' + '\n' + 'A function or method which is defined using "async def" is called ' + 'a\n' + '*coroutine function*. Such a function, when called, returns a\n' + '*coroutine* object. It may contain "await" expressions, as well ' + 'as\n' + '"async with" and "async for" statements. See also the Coroutine\n' + 'Objects section.\n' + '\n' + '\n' + 'Asynchronous generator functions\n' + '--------------------------------\n' + '\n' + 'A function or method which is defined using "async def" and which ' + 'uses\n' + 'the "yield" statement is called a *asynchronous generator ' + 'function*.\n' + 'Such a function, when called, returns an *asynchronous iterator*\n' + 'object which can be used in an "async for" statement to execute ' 'the\n' - ' corresponding argument.\n' - '\n' - ' >>> "The sum of 1 + 2 is {0}".format(1+2)\n' - " 'The sum of 1 + 2 is 3'\n" - '\n' - ' See Format String Syntax for a description of the ' - 'various\n' - ' formatting options that can be specified in format ' - 'strings.\n' - '\n' - ' Note: When formatting a number ("int", "float", ' - '"complex",\n' - ' "decimal.Decimal" and subclasses) with the "n" type ' - '(ex:\n' - ' "\'{:n}\'.format(1234)"), the function temporarily ' - 'sets the\n' - ' "LC_CTYPE" locale to the "LC_NUMERIC" locale to ' - 'decode\n' - ' "decimal_point" and "thousands_sep" fields of ' - '"localeconv()" if\n' - ' they are non-ASCII or longer than 1 byte, and the ' - '"LC_NUMERIC"\n' - ' locale is different than the "LC_CTYPE" locale. This ' - 'temporary\n' - ' change affects other threads.\n' - '\n' - ' Changed in version 3.6.5: When formatting a number with ' - 'the "n"\n' - ' type, the function sets temporarily the "LC_CTYPE" ' - 'locale to the\n' - ' "LC_NUMERIC" locale in some cases.\n' - '\n' - 'str.format_map(mapping)\n' - '\n' - ' Similar to "str.format(**mapping)", except that ' - '"mapping" is used\n' - ' directly and not copied to a "dict". This is useful if ' - 'for example\n' - ' "mapping" is a dict subclass:\n' - '\n' - ' >>> class Default(dict):\n' - ' ... def __missing__(self, key):\n' - ' ... return key\n' - ' ...\n' - " >>> '{name} was born in " - "{country}'.format_map(Default(name='Guido'))\n" - " 'Guido was born in country'\n" - '\n' - ' New in version 3.2.\n' - '\n' - 'str.index(sub[, start[, end]])\n' - '\n' - ' Like "find()", but raise "ValueError" when the ' - 'substring is not\n' - ' found.\n' - '\n' - 'str.isalnum()\n' - '\n' - ' Return true if all characters in the string are ' - 'alphanumeric and\n' - ' there is at least one character, false otherwise. A ' - 'character "c"\n' - ' is alphanumeric if one of the following returns ' - '"True":\n' - ' "c.isalpha()", "c.isdecimal()", "c.isdigit()", or ' - '"c.isnumeric()".\n' - '\n' - 'str.isalpha()\n' - '\n' - ' Return true if all characters in the string are ' - 'alphabetic and\n' - ' there is at least one character, false otherwise. ' - 'Alphabetic\n' - ' characters are those characters defined in the Unicode ' - 'character\n' - ' database as “Letter”, i.e., those with general category ' - 'property\n' - ' being one of “Lm”, “Lt”, “Lu”, “Ll”, or “Lo”. Note ' - 'that this is\n' - ' different from the “Alphabetic” property defined in the ' - 'Unicode\n' - ' Standard.\n' - '\n' - 'str.isdecimal()\n' - '\n' - ' Return true if all characters in the string are decimal ' - 'characters\n' - ' and there is at least one character, false otherwise. ' - 'Decimal\n' - ' characters are those that can be used to form numbers ' - 'in base 10,\n' - ' e.g. U+0660, ARABIC-INDIC DIGIT ZERO. Formally a ' - 'decimal character\n' - ' is a character in the Unicode General Category “Nd”.\n' - '\n' - 'str.isdigit()\n' - '\n' - ' Return true if all characters in the string are digits ' - 'and there is\n' - ' at least one character, false otherwise. Digits ' - 'include decimal\n' - ' characters and digits that need special handling, such ' - 'as the\n' - ' compatibility superscript digits. This covers digits ' - 'which cannot\n' - ' be used to form numbers in base 10, like the Kharosthi ' - 'numbers.\n' - ' Formally, a digit is a character that has the property ' - 'value\n' - ' Numeric_Type=Digit or Numeric_Type=Decimal.\n' - '\n' - 'str.isidentifier()\n' - '\n' - ' Return true if the string is a valid identifier ' - 'according to the\n' - ' language definition, section Identifiers and keywords.\n' - '\n' - ' Use "keyword.iskeyword()" to test for reserved ' - 'identifiers such as\n' - ' "def" and "class".\n' - '\n' - 'str.islower()\n' - '\n' - ' Return true if all cased characters [4] in the string ' - 'are lowercase\n' - ' and there is at least one cased character, false ' - 'otherwise.\n' - '\n' - 'str.isnumeric()\n' - '\n' - ' Return true if all characters in the string are numeric ' - 'characters,\n' - ' and there is at least one character, false otherwise. ' - 'Numeric\n' - ' characters include digit characters, and all characters ' - 'that have\n' - ' the Unicode numeric value property, e.g. U+2155, VULGAR ' - 'FRACTION\n' - ' ONE FIFTH. Formally, numeric characters are those with ' + 'body of the function.\n' + '\n' + 'Calling the asynchronous iterator’s "aiterator.__anext__" method ' + 'will\n' + 'return an *awaitable* which when awaited will execute until it\n' + 'provides a value using the "yield" expression. When the function\n' + 'executes an empty "return" statement or falls off the end, a\n' + '"StopAsyncIteration" exception is raised and the asynchronous ' + 'iterator\n' + 'will have reached the end of the set of values to be yielded.\n' + '\n' + '\n' + 'Built-in functions\n' \ + '------------------\n' + '\n' + 'A built-in function object is a wrapper around a C function. ' + 'Examples\n' + 'of built-in functions are "len()" and "math.sin()" ("math" is a\n' + 'standard built-in module). The number and type of the arguments ' + 'are\n' + 'determined by the C function. Special read-only attributes:\n' + '\n' + '* "__doc__" is the function’s documentation string, or "None" if\n' \ + ' unavailable. See "function.__doc__".\n' + '\n' + '* "__name__" is the function’s name. See "function.__name__".\n' \ + '\n' + '* "__self__" is set to "None" (but see the next item).\n' + '\n' \ + '* "__module__" is the name of the module the function was defined ' + 'in\n' + ' or "None" if unavailable. See "function.__module__".\n' + '\n' \ + '\n' + 'Built-in methods\n' + '----------------\n' + '\n' + 'This is really a different disguise of a built-in function, this ' \ + 'time\n' + 'containing an object passed to the C function as an implicit extra\n' + 'argument. An example of a built-in method is "alist.append()",\n' + 'assuming *alist* is a list object. In this case, the special ' + 'read-only\n' + 'attribute "__self__" is set to the object denoted by *alist*. (The\n' + 'attribute has the same semantics as it does with "other instance\n' + 'methods".)\n' + '\n' \ + '\n' + 'Classes\n' + '-------\n' + '\n' + 'Classes are callable. These objects normally act as factories for ' + 'new\n' \ + 'instances of themselves, but variations are possible for class ' \ + 'types\n' + 'that override "__new__()". The arguments of the call are passed ' + 'to\n' + '"__new__()" and, in the typical case, to "__init__()" to ' + 'initialize\n' \ + 'the new instance.\n' \ + '\n' + '\n' + 'Class Instances\n' \ + '---------------\n' \ + '\n' + 'Instances of arbitrary classes can be made callable by defining a\n' + '"__call__()" method in their class.\n' + '\n' + '\n' + 'Modules\n' + '=======\n' \ + '\n' + 'Modules are a basic organizational unit of Python code, and are\n' + 'created by the import system as invoked either by the "import"\n' + 'statement, or by calling functions such as ' + '"importlib.import_module()"\n' + 'and built-in "__import__()". A module object has a namespace\n' + 'implemented by a "dictionary" object (this is the dictionary\n' + 'referenced by the "__globals__" attribute of functions defined in ' + 'the\n' + 'module). Attribute references are translated to lookups in this\n' + 'dictionary, e.g., "m.x" is equivalent to "m.__dict__["x"]". A ' + 'module\n' + 'object does not contain the code object used to initialize the ' \ + 'module\n' \ + '(since it isn’t needed once the initialization is done).\n' + '\n' + 'Attribute assignment updates the module’s namespace dictionary, ' \ + 'e.g.,\n' \ + '"m.x = 1" is equivalent to "m.__dict__["x"] = 1".\n' + '\n' + '\n' + 'Import-related attributes on module objects\n' + '-------------------------------------------\n' \ + '\n' + 'Module objects have the following attributes that relate to the ' + 'import\n' + 'system. When a module is created using the machinery associated ' + 'with\n' + 'the import system, these attributes are filled in based on the\n' + 'module’s *spec*, before the *loader* executes and loads the ' + 'module.\n' + '\n' + 'To create a module dynamically rather than using the import ' + 'system,\n' + 'it’s recommended to use "importlib.util.module_from_spec()", which\n' + 'will set the various import-controlled attributes to appropriate\n' + 'values. It’s also possible to use the "types.ModuleType" ' \ + 'constructor\n' + 'to create modules directly, but this technique is more error-prone, ' \ + 'as\n' + 'most attributes must be manually set on the module object after it ' + 'has\n' + 'been created when using this approach.\n' + '\n' + 'Caution:\n' + '\n' + ' With the exception of "__name__", it is **strongly** recommended\n' + ' that you rely on "__spec__" and its attributes instead of any of ' \ 'the\n' - ' property value Numeric_Type=Digit, Numeric_Type=Decimal ' + ' other individual attributes listed in this subsection. Note that\n' + ' updating an attribute on "__spec__" will not update the\n' + ' corresponding attribute on the module itself:\n' + '\n' + ' >>> import typing\n' + ' >>> typing.__name__, typing.__spec__.name\n' + " ('typing', 'typing')\n" + " >>> typing.__spec__.name = 'spelling'\n" + ' >>> typing.__name__, typing.__spec__.name\n' \ + " ('typing', 'spelling')\n" + " >>> typing.__name__ = 'keyboard_smashing'\n" + ' >>> typing.__name__, typing.__spec__.name\n' + " ('keyboard_smashing', 'spelling')\n" + '\n' + 'module.__name__\n' + '\n' + ' The name used to uniquely identify the module in the import ' + 'system.\n' + ' For a directly executed module, this will be set to ' \ + '""__main__"".\n' + '\n' + ' This attribute must be set to the fully qualified name of the\n' + ' module. It is expected to match the value of\n' + ' "module.__spec__.name".\n' \ + '\n' + 'module.__spec__\n' + '\n' + ' A record of the module’s import-system-related state.\n' + '\n' + ' Set to the "module spec" that was used when importing the ' + 'module.\n' + ' See Module specs for more details.\n' + '\n' + ' Added in version 3.4.\n' + '\n' \ + 'module.__package__\n' + '\n' + ' The *package* a module belongs to.\n' + '\n' \ + ' If the module is top-level (that is, not a part of any specific\n' + ' package) then the attribute should be set to "\'\'" (the empty\n' + ' string). Otherwise, it should be set to the name of the ' \ + 'module’s\n' + ' package (which can be equal to "module.__name__" if the module\n' + ' itself is a package). See **PEP 366** for further details.\n' + '\n' + ' This attribute is used instead of "__name__" to calculate ' + 'explicit\n' + ' relative imports for main modules. It defaults to "None" for\n' \ + ' modules created dynamically using the "types.ModuleType"\n' + ' constructor; use "importlib.util.module_from_spec()" instead to\n' + ' ensure the attribute is set to a "str".\n' + '\n' + ' It is **strongly** recommended that you use\n' + ' "module.__spec__.parent" instead of "module.__package__".\n' + ' "__package__" is now only used as a fallback if ' + '"__spec__.parent"\n' + ' is not set, and this fallback path is deprecated.\n' + '\n' + ' Changed in version 3.4: This attribute now defaults to "None" ' + 'for\n' \ + ' modules created dynamically using the "types.ModuleType"\n' \ + ' constructor. Previously the attribute was optional.\n' \ + '\n' + ' Changed in version 3.6: The value of "__package__" is expected ' + 'to\n' + ' be the same as "__spec__.parent". "__package__" is now only used ' + 'as\n' + ' a fallback during import resolution if "__spec__.parent" is not\n' \ + ' defined.\n' \ + '\n' + ' Changed in version 3.10: "ImportWarning" is raised if an import\n' + ' resolution falls back to "__package__" instead of\n' + ' "__spec__.parent".\n' + '\n' + ' Changed in version 3.12: Raise "DeprecationWarning" instead of\n' + ' "ImportWarning" when falling back to "__package__" during ' + 'import\n' + ' resolution.\n' + '\n' + 'module.__loader__\n' + '\n' + ' The *loader* object that the import machinery used to load the\n' + ' module.\n' + '\n' + ' This attribute is mostly useful for introspection, but can be ' + 'used\n' + ' for additional loader-specific functionality, for example ' + 'getting\n' + ' data associated with a loader.\n' + '\n' + ' "__loader__" defaults to "None" for modules created dynamically\n' + ' using the "types.ModuleType" constructor; use\n' + ' "importlib.util.module_from_spec()" instead to ensure the ' \ + 'attribute\n' + ' is set to a *loader* object.\n' + '\n' \ + ' It is **strongly** recommended that you use\n' + ' "module.__spec__.loader" instead of "module.__loader__".\n' + '\n' + ' Changed in version 3.4: This attribute now defaults to "None" ' \ + 'for\n' + ' modules created dynamically using the "types.ModuleType"\n' + ' constructor. Previously the attribute was optional.\n' \ + '\n' \ + ' Deprecated since version 3.12, will be removed in version 3.16:\n' + ' Setting "__loader__" on a module while failing to set\n' + ' "__spec__.loader" is deprecated. In Python 3.16, "__loader__" ' + 'will\n' + ' cease to be set or taken into consideration by the import system ' 'or\n' - ' Numeric_Type=Numeric.\n' - '\n' - 'str.isprintable()\n' - '\n' - ' Return true if all characters in the string are ' - 'printable or the\n' - ' string is empty, false otherwise. Nonprintable ' - 'characters are\n' - ' those characters defined in the Unicode character ' - 'database as\n' - ' “Other” or “Separator”, excepting the ASCII space ' - '(0x20) which is\n' - ' considered printable. (Note that printable characters ' - 'in this\n' - ' context are those which should not be escaped when ' - '"repr()" is\n' - ' invoked on a string. It has no bearing on the handling ' - 'of strings\n' - ' written to "sys.stdout" or "sys.stderr".)\n' - '\n' - 'str.isspace()\n' - '\n' - ' Return true if there are only whitespace characters in ' - 'the string\n' - ' and there is at least one character, false otherwise. ' - 'Whitespace\n' - ' characters are those characters defined in the Unicode ' - 'character\n' - ' database as “Other” or “Separator” and those with ' - 'bidirectional\n' - ' property being one of “WS”, “B”, or “S”.\n' - '\n' - 'str.istitle()\n' - '\n' - ' Return true if the string is a titlecased string and ' - 'there is at\n' - ' least one character, for example uppercase characters ' - 'may only\n' - ' follow uncased characters and lowercase characters only ' - 'cased ones.\n' - ' Return false otherwise.\n' - '\n' - 'str.isupper()\n' - '\n' - ' Return true if all cased characters [4] in the string ' - 'are uppercase\n' - ' and there is at least one cased character, false ' - 'otherwise.\n' - '\n' - 'str.join(iterable)\n' - '\n' - ' Return a string which is the concatenation of the ' - 'strings in\n' - ' *iterable*. A "TypeError" will be raised if there are ' - 'any non-\n' - ' string values in *iterable*, including "bytes" ' - 'objects. The\n' - ' separator between elements is the string providing this ' - 'method.\n' + ' the standard library.\n' + '\n' + 'module.__path__\n' + '\n' + ' A (possibly empty) *sequence* of strings enumerating the ' \ + 'locations\n' + ' where the package’s submodules will be found. Non-package ' + 'modules\n' + ' should not have a "__path__" attribute. See __path__ attributes ' + 'on\n' + ' modules for more details.\n' \ + '\n' + ' It is **strongly** recommended that you use\n' + ' "module.__spec__.submodule_search_locations" instead of\n' + ' "module.__path__".\n' + '\n' + 'module.__file__\n' \ + '\n' + 'module.__cached__\n' + '\n' + ' "__file__" and "__cached__" are both optional attributes that ' + 'may\n' + ' or may not be set. Both attributes should be a "str" when they ' + 'are\n' + ' available.\n' + '\n' \ + ' "__file__" indicates the pathname of the file from which the ' + 'module\n' + ' was loaded (if loaded from a file), or the pathname of the ' + 'shared\n' + ' library file for extension modules loaded dynamically from a ' + 'shared\n' + ' library. It might be missing for certain types of modules, such ' + 'as\n' + ' C modules that are statically linked into the interpreter, and ' + 'the\n' + ' import system may opt to leave it unset if it has no semantic\n' + ' meaning (for example, a module loaded from a database).\n' + '\n' + ' If "__file__" is set then the "__cached__" attribute might also ' + 'be\n' + ' set, which is the path to any compiled version of the code ' \ + '(for\n' \ + ' example, a byte-compiled file). The file does not need to exist ' + 'to\n' + ' set this attribute; the path can simply point to where the ' + 'compiled\n' + ' file *would* exist (see **PEP 3147**).\n' + '\n' + ' Note that "__cached__" may be set even if "__file__" is not ' + 'set.\n' \ + ' However, that scenario is quite atypical. Ultimately, the ' + '*loader*\n' + ' is what makes use of the module spec provided by the *finder* ' + '(from\n' + ' which "__file__" and "__cached__" are derived). So if a loader ' + 'can\n' + ' load from a cached module but otherwise does not load from a ' + 'file,\n' + ' that atypical scenario may be appropriate.\n' + '\n' + ' It is **strongly** recommended that you use\n' + ' "module.__spec__.cached" instead of "module.__cached__".\n' + '\n' + '\n' + 'Other writable attributes on module objects\n' + '-------------------------------------------\n' + '\n' \ + 'As well as the import-related attributes listed above, module ' + 'objects\n' + 'also have the following writable attributes:\n' + '\n' + 'module.__doc__\n' + '\n' + ' The module’s documentation string, or "None" if unavailable. ' \ + 'See\n' + ' also: "__doc__ attributes".\n' + '\n' + 'module.__annotations__\n' + '\n' + ' A dictionary containing *variable annotations* collected during\n' + ' module body execution. For best practices on working with\n' \ + ' "__annotations__", please see Annotations Best Practices.\n' \ + '\n' + '\n' + 'Module dictionaries\n' \ + '-------------------\n' + '\n' + 'Module objects also have the following special read-only ' \ + 'attribute:\n' + '\n' + 'module.__dict__\n' + '\n' + ' The module’s namespace as a dictionary object. Uniquely among ' \ + 'the\n' + ' attributes listed here, "__dict__" cannot be accessed as a ' + 'global\n' + ' variable from within a module; it can only be accessed as an\n' + ' attribute on module objects.\n' + '\n' + ' **CPython implementation detail:** Because of the way CPython\n' + ' clears module dictionaries, the module dictionary will be ' \ + 'cleared\n' + ' when the module falls out of scope even if the dictionary still ' + 'has\n' + ' live references. To avoid this, copy the dictionary or keep ' + 'the\n' \ + ' module around while using its dictionary directly.\n' + '\n' + '\n' + 'Custom classes\n' + '==============\n' + '\n' + 'Custom class types are typically created by class definitions (see\n' \ + 'section Class definitions). A class has a namespace implemented by ' + 'a\n' + 'dictionary object. Class attribute references are translated to\n' + 'lookups in this dictionary, e.g., "C.x" is translated to\n' + '"C.__dict__["x"]" (although there are a number of hooks which ' \ + 'allow\n' + 'for other means of locating attributes). When the attribute name ' + 'is\n' + 'not found there, the attribute search continues in the base ' + 'classes.\n' + 'This search of the base classes uses the C3 method resolution ' + 'order\n' + 'which behaves correctly even in the presence of ‘diamond’ ' + 'inheritance\n' + 'structures where there are multiple inheritance paths leading back ' + 'to\n' + 'a common ancestor. Additional details on the C3 MRO used by Python ' + 'can\n' + 'be found at The Python 2.3 Method Resolution Order.\n' + '\n' + 'When a class attribute reference (for class "C", say) would yield ' + 'a\n' + 'class method object, it is transformed into an instance method ' + 'object\n' + 'whose "__self__" attribute is "C". When it would yield a\n' + '"staticmethod" object, it is transformed into the object wrapped ' \ + 'by\n' + 'the static method object. See section Implementing Descriptors for\n' + 'another way in which attributes retrieved from a class may differ ' + 'from\n' + 'those actually contained in its "__dict__".\n' + '\n' + 'Class attribute assignments update the class’s dictionary, never ' + 'the\n' + 'dictionary of a base class.\n' + '\n' + 'A class object can be called (see above) to yield a class instance\n' + '(see below).\n' + '\n' \ + '\n' + 'Special attributes\n' + '------------------\n' + '\n' + '+----------------------------------------------------+----------------------------------------------------+\n' \ + '| Attribute | ' + 'Meaning |\n' \ + '|====================================================|====================================================|\n' + '| type.__name__ | The class’s ' + 'name. See also: "__name__ attributes". |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '| type.__qualname__ | The class’s ' + '*qualified name*. See also: |\n' \ + '| | ' + '"__qualname__ attributes". |\n' \ + '+----------------------------------------------------+----------------------------------------------------+\n' + '| type.__module__ | The name of ' + 'the module in which the class was |\n' + '| | ' + 'defined. |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' \ + '| type.__dict__ | A "mapping ' + 'proxy" providing a read-only view of |\n' + '| | the class’s ' + 'namespace. See also: "__dict__ |\n' + '| | ' + 'attributes". |\n' \ + '+----------------------------------------------------+----------------------------------------------------+\n' \ + '| type.__bases__ | A "tuple" ' + 'containing the class’s bases. In most |\n' \ + '| | cases, for a ' + 'class defined as "class X(A, B, C)", |\n' \ + '| | ' \ + '"X.__bases__" will be exactly equal to "(A, B, |\n' + '| | ' + 'C)". |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '| type.__doc__ | The class’s ' + 'documentation string, or "None" if |\n' \ + '| | undefined. ' + 'Not inherited by subclasses. |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' \ + '| type.__annotations__ | A dictionary ' + 'containing *variable annotations* |\n' + '| | collected ' + 'during class body execution. For best |\n' + '| | practices on ' + 'working with "__annotations__", |\n' + '| | please see ' \ + 'Annotations Best Practices. Caution: |\n' + '| | Accessing ' + 'the "__annotations__" attribute of a |\n' + '| | class object ' + 'directly may yield incorrect results |\n' + '| | in the ' + 'presence of metaclasses. In addition, the |\n' + '| | attribute ' \ + 'may not exist for some classes. Use |\n' + '| | ' + '"inspect.get_annotations()" to retrieve class |\n' + '| | annotations ' + 'safely. |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '| type.__type_params__ | A "tuple" ' + 'containing the type parameters of a |\n' + '| | generic ' + 'class. Added in version 3.12. |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '| type.__mro__ | The "tuple" ' + 'of classes that are considered when |\n' + '| | looking for ' + 'base classes during method resolution. |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '\n' + '\n' + 'Special methods\n' + '---------------\n' + '\n' \ + 'In addition to the special attributes described above, all Python\n' \ + 'classes also have the following two methods available:\n' + '\n' + 'type.mro()\n' + '\n' + ' This method can be overridden by a metaclass to customize the\n' + ' method resolution order for its instances. It is called at ' + 'class\n' + ' instantiation, and its result is stored in "__mro__".\n' \ + '\n' + 'type.__subclasses__()\n' + '\n' \ + ' Each class keeps a list of weak references to its immediate\n' + ' subclasses. This method returns a list of all those references\n' + ' still alive. The list is in definition order. Example:\n' \ + '\n' \ + ' >>> class A: pass\n' \ + ' >>> class B(A): pass\n' + ' >>> A.__subclasses__()\n' \ + " []\n" + '\n' + '\n' \ + 'Class instances\n' + '===============\n' + '\n' + 'A class instance is created by calling a class object (see above). ' + 'A\n' + 'class instance has a namespace implemented as a dictionary which ' + 'is\n' + 'the first place in which attribute references are searched. When ' + 'an\n' + 'attribute is not found there, and the instance’s class has an\n' + 'attribute by that name, the search continues with the class\n' \ + 'attributes. If a class attribute is found that is a user-defined\n' \ + 'function object, it is transformed into an instance method object\n' + 'whose "__self__" attribute is the instance. Static method and ' + 'class\n' + 'method objects are also transformed; see above under “Classes”. ' \ + 'See\n' + 'section Implementing Descriptors for another way in which ' + 'attributes\n' + 'of a class retrieved via its instances may differ from the objects\n' \ + 'actually stored in the class’s "__dict__". If no class attribute ' + 'is\n' + 'found, and the object’s class has a "__getattr__()" method, that ' \ + 'is\n' \ + 'called to satisfy the lookup.\n' + '\n' + 'Attribute assignments and deletions update the instance’s ' + 'dictionary,\n' + 'never a class’s dictionary. If the class has a "__setattr__()" or\n' + '"__delattr__()" method, this is called instead of updating the\n' \ + 'instance dictionary directly.\n' \ + '\n' + 'Class instances can pretend to be numbers, sequences, or mappings ' + 'if\n' + 'they have methods with certain special names. See section Special\n' + 'method names.\n' + '\n' + '\n' + 'Special attributes\n' + '------------------\n' + '\n' + 'object.__class__\n' + '\n' + ' The class to which a class instance belongs.\n' + '\n' + 'object.__dict__\n' + '\n' + ' A dictionary or other mapping object used to store an object’s\n' + ' (writable) attributes. Not all instances have a "__dict__"\n' + ' attribute; see the section on __slots__ for more details.\n' + '\n' + '\n' \ + 'I/O objects (also known as file objects)\n' + '========================================\n' \ + '\n' + 'A *file object* represents an open file. Various shortcuts are\n' + 'available to create file objects: the "open()" built-in function, ' + 'and\n' + 'also "os.popen()", "os.fdopen()", and the "makefile()" method of\n' + 'socket objects (and perhaps by other functions or methods provided ' \ + 'by\n' + 'extension modules).\n' + '\n' + 'The objects "sys.stdin", "sys.stdout" and "sys.stderr" are ' + 'initialized\n' \ + 'to file objects corresponding to the interpreter’s standard input,\n' \ + 'output and error streams; they are all open in text mode and ' + 'therefore\n' + 'follow the interface defined by the "io.TextIOBase" abstract ' + 'class.\n' + '\n' + '\n' \ + 'Internal types\n' + '==============\n' + '\n' + 'A few types used internally by the interpreter are exposed to the\n' + 'user. Their definitions may change with future versions of the\n' + 'interpreter, but they are mentioned here for completeness.\n' + '\n' \ + '\n' + 'Code objects\n' + '------------\n' + '\n' + 'Code objects represent *byte-compiled* executable Python code, or\n' + '*bytecode*. The difference between a code object and a function ' \ + 'object\n' + 'is that the function object contains an explicit reference to the\n' + 'function’s globals (the module in which it was defined), while a ' + 'code\n' + 'object contains no context; also the default argument values are\n' + 'stored in the function object, not in the code object (because ' + 'they\n' + 'represent values calculated at run-time). Unlike function ' + 'objects,\n' + 'code objects are immutable and contain no references (directly or\n' \ + 'indirectly) to mutable objects.\n' \ + '\n' + '\n' + 'Special read-only attributes\n' \ + '~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n' + '\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '| codeobject.co_name | The function ' + 'name |\n' \ + '+----------------------------------------------------+----------------------------------------------------+\n' + '| codeobject.co_qualname | The fully ' + 'qualified function name Added in |\n' + '| | version ' + '3.11. |\n' \ + '+----------------------------------------------------+----------------------------------------------------+\n' \ + '| codeobject.co_argcount | The total ' \ + 'number of positional *parameters* |\n' + '| | (including ' \ + 'positional-only parameters and |\n' + '| | parameters ' + 'with default values) that the function |\n' + '| | ' + 'has |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '| codeobject.co_posonlyargcount | The number ' + 'of positional-only *parameters* |\n' \ + '| | (including ' + 'arguments with default values) that the |\n' + '| | function ' + 'has |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '| codeobject.co_kwonlyargcount | The number ' + 'of keyword-only *parameters* (including |\n' + '| | arguments ' + 'with default values) that the function |\n' + '| | ' + 'has |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' \ + '| codeobject.co_nlocals | The number ' + 'of local variables used by the function |\n' + '| | (including ' + 'parameters) |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '| codeobject.co_varnames | A "tuple" ' + 'containing the names of the local |\n' + '| | variables in ' + 'the function (starting with the |\n' \ + '| | parameter ' + 'names) |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '| codeobject.co_cellvars | A "tuple" ' + 'containing the names of local variables |\n' + '| | that are ' + 'referenced by nested functions inside the |\n' + '| | ' + 'function |\n' \ + '+----------------------------------------------------+----------------------------------------------------+\n' + '| codeobject.co_freevars | A "tuple" ' + 'containing the names of free variables |\n' + '| | in the ' \ + 'function |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '| codeobject.co_code | A string ' \ + 'representing the sequence of *bytecode* |\n' + '| | instructions ' + 'in the function |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '| codeobject.co_consts | A "tuple" ' \ + 'containing the literals used by the |\n' + '| | *bytecode* ' + 'in the function |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '| codeobject.co_names | A "tuple" ' + 'containing the names used by the |\n' + '| | *bytecode* ' \ + 'in the function |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '| codeobject.co_filename | The name of ' + 'the file from which the code was |\n' + '| | ' \ + 'compiled |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '| codeobject.co_firstlineno | The line ' + 'number of the first line of the function |\n' \ + '+----------------------------------------------------+----------------------------------------------------+\n' + '| codeobject.co_lnotab | A string ' \ + 'encoding the mapping from *bytecode* |\n' \ + '| | offsets to ' + 'line numbers. For details, see the |\n' + '| | source code ' + 'of the interpreter. Deprecated since |\n' + '| | version ' \ + '3.12: This attribute of code objects is |\n' + '| | deprecated, ' + 'and may be removed in Python 3.15. |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '| codeobject.co_stacksize | The required ' + 'stack size of the code object |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '| codeobject.co_flags | An "integer" ' + 'encoding a number of flags for the |\n' + '| | ' + 'interpreter. |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '\n' \ + 'The following flag bits are defined for "co_flags": bit "0x04" is ' + 'set\n' + 'if the function uses the "*arguments" syntax to accept an ' + 'arbitrary\n' + 'number of positional arguments; bit "0x08" is set if the function ' + 'uses\n' + 'the "**keywords" syntax to accept arbitrary keyword arguments; bit\n' + '"0x20" is set if the function is a generator. See Code Objects Bit\n' + 'Flags for details on the semantics of each flags that might be\n' + 'present.\n' + '\n' + 'Future feature declarations ("from __future__ import division") ' + 'also\n' + 'use bits in "co_flags" to indicate whether a code object was ' + 'compiled\n' + 'with a particular feature enabled: bit "0x2000" is set if the ' + 'function\n' + 'was compiled with future division enabled; bits "0x10" and ' + '"0x1000"\n' + 'were used in earlier versions of Python.\n' \ + '\n' \ + 'Other bits in "co_flags" are reserved for internal use.\n' \ + '\n' \ + 'If a code object represents a function, the first item in ' + '"co_consts"\n' \ + 'is the documentation string of the function, or "None" if ' + 'undefined.\n' + '\n' \ + '\n' + 'Methods on code objects\n' + '~~~~~~~~~~~~~~~~~~~~~~~\n' \ + '\n' \ + 'codeobject.co_positions()\n' + '\n' + ' Returns an iterable over the source code positions of each\n' + ' *bytecode* instruction in the code object.\n' \ + '\n' + ' The iterator returns "tuple"s containing the "(start_line,\n' + ' end_line, start_column, end_column)". The *i-th* tuple ' + 'corresponds\n' + ' to the position of the source code that compiled to the *i-th* ' + 'code\n' + ' unit. Column information is 0-indexed utf-8 byte offsets on the\n' + ' given source line.\n' \ + '\n' + ' This positional information can be missing. A non-exhaustive ' + 'lists\n' \ + ' of cases where this may happen:\n' + '\n' + ' * Running the interpreter with "-X" "no_debug_ranges".\n' + '\n' + ' * Loading a pyc file compiled while using "-X" ' \ + '"no_debug_ranges".\n' + '\n' + ' * Position tuples corresponding to artificial instructions.\n' + '\n' + ' * Line and column numbers that can’t be represented due to\n' \ + ' implementation specific limitations.\n' + '\n' \ + ' When this occurs, some or all of the tuple elements can be ' + '"None".\n' \ + '\n' \ + ' Added in version 3.11.\n' + '\n' + ' Note:\n' + '\n' + ' This feature requires storing column positions in code ' \ + 'objects\n' \ + ' which may result in a small increase of disk usage of ' \ + 'compiled\n' \ + ' Python files or interpreter memory usage. To avoid storing ' \ + 'the\n' + ' extra information and/or deactivate printing the extra ' + 'traceback\n' + ' information, the "-X" "no_debug_ranges" command line flag or ' + 'the\n' + ' "PYTHONNODEBUGRANGES" environment variable can be used.\n' + '\n' + 'codeobject.co_lines()\n' + '\n' + ' Returns an iterator that yields information about successive ' + 'ranges\n' + ' of *bytecode*s. Each item yielded is a "(start, end, lineno)"\n' + ' "tuple":\n' + '\n' + ' * "start" (an "int") represents the offset (inclusive) of the ' + 'start\n' + ' of the *bytecode* range\n' + '\n' + ' * "end" (an "int") represents the offset (exclusive) of the end ' \ + 'of\n' \ + ' the *bytecode* range\n' + '\n' \ + ' * "lineno" is an "int" representing the line number of the\n' + ' *bytecode* range, or "None" if the bytecodes in the given ' + 'range\n' \ + ' have no line number\n' + '\n' + ' The items yielded will have the following properties:\n' + '\n' + ' * The first range yielded will have a "start" of 0.\n' \ + '\n' + ' * The "(start, end)" ranges will be non-decreasing and ' + 'consecutive.\n' + ' That is, for any pair of "tuple"s, the "start" of the second ' + 'will\n' + ' be equal to the "end" of the first.\n' + '\n' + ' * No range will be backwards: "end >= start" for all triples.\n' + '\n' + ' * The last "tuple" yielded will have "end" equal to the size of ' + 'the\n' + ' *bytecode*.\n' + '\n' \ + ' Zero-width ranges, where "start == end", are allowed. ' + 'Zero-width\n' + ' ranges are used for lines that are present in the source code, ' + 'but\n' + ' have been eliminated by the *bytecode* compiler.\n' + '\n' \ + ' Added in version 3.10.\n' + '\n' + ' See also:\n' + '\n' + ' **PEP 626** - Precise line numbers for debugging and other ' + 'tools.\n' + ' The PEP that introduced the "co_lines()" method.\n' + '\n' + 'codeobject.replace(**kwargs)\n' + '\n' \ + ' Return a copy of the code object with new values for the ' \ + 'specified\n' + ' fields.\n' + '\n' + ' Added in version 3.8.\n' \ + '\n' + '\n' + 'Frame objects\n' + '-------------\n' + '\n' \ + 'Frame objects represent execution frames. They may occur in ' + 'traceback\n' \ + 'objects, and are also passed to registered trace functions.\n' + '\n' + '\n' + 'Special read-only attributes\n' + '~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n' + '\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '| frame.f_back | Points to ' + 'the previous stack frame (towards the |\n' + '| | caller), or ' + '"None" if this is the bottom stack |\n' + '| | ' + 'frame |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '| frame.f_code | The code ' + 'object being executed in this frame. |\n' + '| | Accessing ' + 'this attribute raises an auditing event |\n' + '| | ' + '"object.__getattr__" with arguments "obj" and |\n' + '| | ' \ + '""f_code"". |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '| frame.f_locals | The ' \ + 'dictionary used by the frame to look up local |\n' + '| | ' + 'variables |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '| frame.f_globals | The ' + 'dictionary used by the frame to look up global |\n' + '| | ' + 'variables |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '| frame.f_builtins | The ' + 'dictionary used by the frame to look up built- |\n' + '| | in ' + '(intrinsic) names |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '| frame.f_lasti | The “precise ' + 'instruction” of the frame object |\n' + '| | (this is an ' \ + 'index into the *bytecode* string of |\n' + '| | the code ' + 'object) |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '\n' + '\n' + 'Special writable attributes\n' + '~~~~~~~~~~~~~~~~~~~~~~~~~~~\n' + '\n' \ + '+----------------------------------------------------+----------------------------------------------------+\n' + '| frame.f_trace | If not ' + '"None", this is a function called for |\n' + '| | various ' \ + 'events during code execution (this is used |\n' + '| | by ' + 'debuggers). Normally an event is triggered for |\n' + '| | each new ' + 'source line (see "f_trace_lines"). |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' \ + '| frame.f_trace_lines | Set this ' + 'attribute to "False" to disable |\n' + '| | triggering a ' \ + 'tracing event for each source line. |\n' \ + '+----------------------------------------------------+----------------------------------------------------+\n' + '| frame.f_trace_opcodes | Set this ' + 'attribute to "True" to allow per-opcode |\n' + '| | events to be ' + 'requested. Note that this may lead to |\n' + '| | undefined ' + 'interpreter behaviour if exceptions |\n' + '| | raised by ' + 'the trace function escape to the |\n' + '| | function ' + 'being traced. |\n' \ + '+----------------------------------------------------+----------------------------------------------------+\n' + '| frame.f_lineno | The current ' + 'line number of the frame – writing to |\n' \ + '| | this from ' + 'within a trace function jumps to the |\n' + '| | given line ' + '(only for the bottom-most frame). A |\n' + '| | debugger can ' + 'implement a Jump command (aka Set |\n' + '| | Next ' + 'Statement) by writing to this attribute. |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '\n' + '\n' \ + 'Frame object methods\n' + '~~~~~~~~~~~~~~~~~~~~\n' \ + '\n' + 'Frame objects support one method:\n' + '\n' + 'frame.clear()\n' + '\n' + ' This method clears all references to local variables held by ' + 'the\n' + ' frame. Also, if the frame belonged to a *generator*, the ' + 'generator\n' + ' is finalized. This helps break reference cycles involving ' + 'frame\n' + ' objects (for example when catching an exception and storing its\n' + ' traceback for later use).\n' + '\n' + ' "RuntimeError" is raised if the frame is currently executing.\n' + '\n' + ' Added in version 3.4.\n' + '\n' + '\n' + 'Traceback objects\n' + '-----------------\n' + '\n' + 'Traceback objects represent the stack trace of an exception. A\n' + 'traceback object is implicitly created when an exception occurs, ' + 'and\n' + 'may also be explicitly created by calling "types.TracebackType".\n' + '\n' + 'Changed in version 3.7: Traceback objects can now be explicitly\n' + 'instantiated from Python code.\n' \ + '\n' + 'For implicitly created tracebacks, when the search for an ' + 'exception\n' + 'handler unwinds the execution stack, at each unwound level a ' + 'traceback\n' + 'object is inserted in front of the current traceback. When an\n' \ + 'exception handler is entered, the stack trace is made available to ' + 'the\n' + 'program. (See section The try statement.) It is accessible as the\n' + 'third item of the tuple returned by "sys.exc_info()", and as the\n' + '"__traceback__" attribute of the caught exception.\n' + '\n' \ + 'When the program contains no suitable handler, the stack trace is\n' + 'written (nicely formatted) to the standard error stream; if the\n' + 'interpreter is interactive, it is also made available to the user ' + 'as\n' \ + '"sys.last_traceback".\n' + '\n' + 'For explicitly created tracebacks, it is up to the creator of the\n' + 'traceback to determine how the "tb_next" attributes should be ' + 'linked\n' + 'to form a full stack trace.\n' + '\n' + 'Special read-only attributes:\n' + '\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '| traceback.tb_frame | Points to ' + 'the execution frame of the current |\n' + '| | level. ' \ + 'Accessing this attribute raises an |\n' + '| | auditing ' + 'event "object.__getattr__" with arguments |\n' + '| | "obj" and ' + '""tb_frame"". |\n' \ + '+----------------------------------------------------+----------------------------------------------------+\n' + '| traceback.tb_lineno | Gives the ' + 'line number where the exception occurred |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' \ + '| traceback.tb_lasti | Indicates ' \ + 'the “precise instruction”. |\n' + '+----------------------------------------------------+----------------------------------------------------+\n' + '\n' + 'The line number and last instruction in the traceback may differ ' + 'from\n' + 'the line number of its frame object if the exception occurred in a\n' \ + '"try" statement with no matching except clause or with a "finally"\n' + 'clause.\n' + '\n' + 'traceback.tb_next\n' + '\n' \ + ' The special writable attribute "tb_next" is the next level in ' + 'the\n' \ + ' stack trace (towards the frame where the exception occurred), ' \ + 'or\n' + ' "None" if there is no next level.\n' + '\n' \ + ' Changed in version 3.7: This attribute is now writable\n' + '\n' \ + '\n' \ + 'Slice objects\n' \ + '-------------\n' + '\n' \ + 'Slice objects are used to represent slices for "__getitem__()"\n' \ + 'methods. They are also created by the built-in "slice()" ' \ + 'function.\n' + '\n' + 'Special read-only attributes: "start" is the lower bound; "stop" ' + 'is\n' \ + 'the upper bound; "step" is the step value; each is "None" if ' \ + 'omitted.\n' + 'These attributes can have any type.\n' \ + '\n' + 'Slice objects support one method:\n' + '\n' \ + 'slice.indices(self, length)\n' \ + '\n' + ' This method takes a single integer argument *length* and ' + 'computes\n' + ' information about the slice that the slice object would describe ' + 'if\n' + ' applied to a sequence of *length* items. It returns a tuple of\n' + ' three integers; respectively these are the *start* and *stop*\n' + ' indices and the *step* or stride length of the slice. Missing ' + 'or\n' + ' out-of-bounds indices are handled in a manner consistent with\n' + ' regular slices.\n' + '\n' + '\n' + 'Static method objects\n' + '---------------------\n' \ + '\n' \ + 'Static method objects provide a way of defeating the transformation ' \ + 'of\n' + 'function objects to method objects described above. A static ' \ + 'method\n' + 'object is a wrapper around any other object, usually a ' + 'user-defined\n' \ + 'method object. When a static method object is retrieved from a ' + 'class\n' + 'or a class instance, the object actually returned is the wrapped\n' + 'object, which is not subject to any further transformation. Static\n' + 'method objects are also callable. Static method objects are created ' + 'by\n' + 'the built-in "staticmethod()" constructor.\n' + '\n' + '\n' \ + 'Class method objects\n' \ + '--------------------\n' + '\n' \ + 'A class method object, like a static method object, is a wrapper\n' + 'around another object that alters the way in which that object is\n' + 'retrieved from classes and class instances. The behaviour of class\n' + 'method objects upon such retrieval is described above, under ' + '“instance\n' + 'methods”. Class method objects are created by the built-in\n' + '"classmethod()" constructor.\n', + 'typesfunctions': 'Functions\n' + '*********\n' + '\n' + 'Function objects are created by function definitions. The ' + 'only\n' \ + 'operation on a function object is to call it: ' \ + '"func(argument-list)".\n' + '\n' + 'There are really two flavors of function objects: built-in ' \ + 'functions\n' + 'and user-defined functions. Both support the same ' + 'operation (to call\n' + 'the function), but the implementation is different, hence ' + 'the\n' + 'different object types.\n' \ + '\n' \ + 'See Function definitions for more information.\n', + 'typesmapping': 'Mapping Types — "dict"\n' + '**********************\n' + '\n' \ + 'A *mapping* object maps *hashable* values to arbitrary ' \ + 'objects.\n' + 'Mappings are mutable objects. There is currently only one ' + 'standard\n' + 'mapping type, the *dictionary*. (For other containers see ' + 'the built-\n' + 'in "list", "set", and "tuple" classes, and the "collections" ' \ + 'module.)\n' \ + '\n' \ + 'A dictionary’s keys are *almost* arbitrary values. Values ' + 'that are\n' + 'not *hashable*, that is, values containing lists, ' + 'dictionaries or\n' + 'other mutable types (that are compared by value rather than ' + 'by object\n' + 'identity) may not be used as keys. Values that compare equal ' \ + '(such as\n' + '"1", "1.0", and "True") can be used interchangeably to index ' + 'the same\n' + 'dictionary entry.\n' + '\n' + 'class dict(**kwargs)\n' + 'class dict(mapping, **kwargs)\n' + 'class dict(iterable, **kwargs)\n' \ + '\n' + ' Return a new dictionary initialized from an optional ' + 'positional\n' + ' argument and a possibly empty set of keyword arguments.\n' \ + '\n' \ + ' Dictionaries can be created by several means:\n' + '\n' + ' * Use a comma-separated list of "key: value" pairs within ' \ + 'braces:\n' + ' "{\'jack\': 4098, \'sjoerd\': 4127}" or "{4098: ' \ + "'jack', 4127:\n" + ' \'sjoerd\'}"\n' \ + '\n' + ' * Use a dict comprehension: "{}", "{x: x ** 2 for x in ' + 'range(10)}"\n' \ + '\n' + ' * Use the type constructor: "dict()", "dict([(\'foo\', ' + "100), ('bar',\n" + ' 200)])", "dict(foo=100, bar=200)"\n' + '\n' \ + ' If no positional argument is given, an empty dictionary ' + 'is created.\n' + ' If a positional argument is given and it defines a ' \ + '"keys()" method,\n' \ + ' a dictionary is created by calling "__getitem__()" on the ' + 'argument\n' \ + ' with each returned key from the method. Otherwise, the ' \ + 'positional\n' \ + ' argument must be an *iterable* object. Each item in the ' \ + 'iterable\n' + ' must itself be an iterable with exactly two elements. ' \ + 'The first\n' + ' element of each item becomes a key in the new dictionary, ' + 'and the\n' + ' second element the corresponding value. If a key occurs ' + 'more than\n' \ + ' once, the last value for that key becomes the ' + 'corresponding value\n' \ + ' in the new dictionary.\n' + '\n' \ + ' If keyword arguments are given, the keyword arguments and ' \ + 'their\n' + ' values are added to the dictionary created from the ' \ + 'positional\n' + ' argument. If a key being added is already present, the ' + 'value from\n' \ + ' the keyword argument replaces the value from the ' \ + 'positional\n' + ' argument.\n' + '\n' \ + ' To illustrate, the following examples all return a ' + 'dictionary equal\n' + ' to "{"one": 1, "two": 2, "three": 3}":\n' + '\n' \ + ' >>> a = dict(one=1, two=2, three=3)\n' + " >>> b = {'one': 1, 'two': 2, 'three': 3}\n" \ + " >>> c = dict(zip(['one', 'two', 'three'], [1, 2, 3]))\n" \ + " >>> d = dict([('two', 2), ('one', 1), ('three', 3)])\n" \ + " >>> e = dict({'three': 3, 'one': 1, 'two': 2})\n" \ + " >>> f = dict({'one': 1, 'three': 3}, two=2)\n" + ' >>> a == b == c == d == e == f\n' + ' True\n' + '\n' \ + ' Providing keyword arguments as in the first example only ' \ + 'works for\n' + ' keys that are valid Python identifiers. Otherwise, any ' + 'valid keys\n' \ + ' can be used.\n' + '\n' + ' These are the operations that dictionaries support (and ' + 'therefore,\n' \ + ' custom mapping types should support too):\n' + '\n' + ' list(d)\n' + '\n' + ' Return a list of all the keys used in the dictionary ' + '*d*.\n' \ + '\n' \ + ' len(d)\n' \ + '\n' \ + ' Return the number of items in the dictionary *d*.\n' \ + '\n' + ' d[key]\n' + '\n' + ' Return the item of *d* with key *key*. Raises a ' + '"KeyError" if\n' \ + ' *key* is not in the map.\n' + '\n' \ + ' If a subclass of dict defines a method "__missing__()" ' \ + 'and *key*\n' + ' is not present, the "d[key]" operation calls that ' + 'method with\n' + ' the key *key* as argument. The "d[key]" operation ' + 'then returns\n' + ' or raises whatever is returned or raised by the\n' + ' "__missing__(key)" call. No other operations or ' \ + 'methods invoke\n' + ' "__missing__()". If "__missing__()" is not defined, ' + '"KeyError"\n' \ + ' is raised. "__missing__()" must be a method; it cannot ' + 'be an\n' \ + ' instance variable:\n' + '\n' + ' >>> class Counter(dict):\n' \ + ' ... def __missing__(self, key):\n' \ + ' ... return 0\n' + ' ...\n' \ + ' >>> c = Counter()\n' \ + " >>> c['red']\n" + ' 0\n' + " >>> c['red'] += 1\n" \ + " >>> c['red']\n" + ' 1\n' + '\n' \ + ' The example above shows part of the implementation of\n' \ + ' "collections.Counter". A different "__missing__" ' \ + 'method is used\n' + ' by "collections.defaultdict".\n' + '\n' + ' d[key] = value\n' \ + '\n' + ' Set "d[key]" to *value*.\n' \ + '\n' + ' del d[key]\n' + '\n' + ' Remove "d[key]" from *d*. Raises a "KeyError" if ' + '*key* is not\n' \ + ' in the map.\n' \ + '\n' + ' key in d\n' \ + '\n' \ + ' Return "True" if *d* has a key *key*, else "False".\n' + '\n' + ' key not in d\n' + '\n' + ' Equivalent to "not key in d".\n' + '\n' + ' iter(d)\n' \ + '\n' + ' Return an iterator over the keys of the dictionary. ' \ + 'This is a\n' + ' shortcut for "iter(d.keys())".\n' \ + '\n' \ + ' clear()\n' \ + '\n' \ + ' Remove all items from the dictionary.\n' + '\n' + ' copy()\n' + '\n' + ' Return a shallow copy of the dictionary.\n' + '\n' + ' classmethod fromkeys(iterable, value=None, /)\n' + '\n' + ' Create a new dictionary with keys from *iterable* and ' + 'values set\n' \ + ' to *value*.\n' + '\n' + ' "fromkeys()" is a class method that returns a new ' \ + 'dictionary.\n' \ + ' *value* defaults to "None". All of the values refer ' + 'to just a\n' + ' single instance, so it generally doesn’t make sense ' + 'for *value*\n' + ' to be a mutable object such as an empty list. To get ' + 'distinct\n' + ' values, use a dict comprehension instead.\n' + '\n' + ' get(key, default=None)\n' + '\n' + ' Return the value for *key* if *key* is in the ' + 'dictionary, else\n' + ' *default*. If *default* is not given, it defaults to ' + '"None", so\n' \ + ' that this method never raises a "KeyError".\n' \ + '\n' + ' items()\n' \ + '\n' + ' Return a new view of the dictionary’s items ("(key, ' + 'value)"\n' \ + ' pairs). See the documentation of view objects.\n' + '\n' + ' keys()\n' + '\n' + ' Return a new view of the dictionary’s keys. See the\n' + ' documentation of view objects.\n' \ + '\n' \ + ' pop(key[, default])\n' + '\n' \ + ' If *key* is in the dictionary, remove it and return ' + 'its value,\n' \ + ' else return *default*. If *default* is not given and ' + '*key* is\n' + ' not in the dictionary, a "KeyError" is raised.\n' + '\n' + ' popitem()\n' + '\n' \ + ' Remove and return a "(key, value)" pair from the ' \ + 'dictionary.\n' + ' Pairs are returned in LIFO (last-in, first-out) ' + 'order.\n' + '\n' + ' "popitem()" is useful to destructively iterate over a\n' + ' dictionary, as often used in set algorithms. If the ' \ + 'dictionary\n' + ' is empty, calling "popitem()" raises a "KeyError".\n' + '\n' + ' Changed in version 3.7: LIFO order is now guaranteed. ' + 'In prior\n' \ + ' versions, "popitem()" would return an arbitrary ' + 'key/value pair.\n' + '\n' + ' reversed(d)\n' + '\n' \ + ' Return a reverse iterator over the keys of the ' \ + 'dictionary. This\n' + ' is a shortcut for "reversed(d.keys())".\n' \ + '\n' + ' Added in version 3.8.\n' \ + '\n' \ + ' setdefault(key, default=None)\n' + '\n' \ + ' If *key* is in the dictionary, return its value. If ' + 'not, insert\n' + ' *key* with a value of *default* and return *default*. ' + '*default*\n' + ' defaults to "None".\n' + '\n' \ + ' update([other])\n' + '\n' \ + ' Update the dictionary with the key/value pairs from ' + '*other*,\n' \ + ' overwriting existing keys. Return "None".\n' + '\n' + ' "update()" accepts either another object with a ' + '"keys()" method\n' \ + ' (in which case "__getitem__()" is called with every ' + 'key returned\n' + ' from the method) or an iterable of key/value pairs (as ' + 'tuples or\n' + ' other iterables of length two). If keyword arguments ' + 'are\n' + ' specified, the dictionary is then updated with those ' + 'key/value\n' + ' pairs: "d.update(red=1, blue=2)".\n' + '\n' + ' values()\n' \ + '\n' + ' Return a new view of the dictionary’s values. See ' \ + 'the\n' + ' documentation of view objects.\n' + '\n' \ + ' An equality comparison between one "dict.values()" ' + 'view and\n' + ' another will always return "False". This also applies ' \ + 'when\n' + ' comparing "dict.values()" to itself:\n' \ + '\n' + " >>> d = {'a': 1}\n" + ' >>> d.values() == d.values()\n' + ' False\n' + '\n' \ + ' d | other\n' \ + '\n' + ' Create a new dictionary with the merged keys and ' \ + 'values of *d*\n' + ' and *other*, which must both be dictionaries. The ' \ + 'values of\n' + ' *other* take priority when *d* and *other* share ' + 'keys.\n' + '\n' \ + ' Added in version 3.9.\n' \ + '\n' \ + ' d |= other\n' + '\n' + ' Update the dictionary *d* with keys and values from ' + '*other*,\n' \ + ' which may be either a *mapping* or an *iterable* of ' \ + 'key/value\n' + ' pairs. The values of *other* take priority when *d* ' \ + 'and *other*\n' + ' share keys.\n' + '\n' \ + ' Added in version 3.9.\n' \ + '\n' + ' Dictionaries compare equal if and only if they have the ' \ + 'same "(key,\n' + ' value)" pairs (regardless of ordering). Order comparisons ' \ + '(‘<’,\n' + ' ‘<=’, ‘>=’, ‘>’) raise "TypeError".\n' + '\n' + ' Dictionaries preserve insertion order. Note that ' + 'updating a key\n' \ + ' does not affect the order. Keys added after deletion are ' + 'inserted\n' \ + ' at the end.\n' + '\n' + ' >>> d = {"one": 1, "two": 2, "three": 3, "four": 4}\n' + ' >>> d\n' + " {'one': 1, 'two': 2, 'three': 3, 'four': 4}\n" + ' >>> list(d)\n' \ + " ['one', 'two', 'three', 'four']\n" \ + ' >>> list(d.values())\n' + ' [1, 2, 3, 4]\n' + ' >>> d["one"] = 42\n' + ' >>> d\n' + " {'one': 42, 'two': 2, 'three': 3, 'four': 4}\n" + ' >>> del d["two"]\n' + ' >>> d["two"] = None\n' + ' >>> d\n' + " {'one': 42, 'three': 3, 'four': 4, 'two': None}\n" + '\n' \ + ' Changed in version 3.7: Dictionary order is guaranteed to ' \ + 'be\n' \ + ' insertion order. This behavior was an implementation ' + 'detail of\n' \ + ' CPython from 3.6.\n' + '\n' + ' Dictionaries and dictionary views are reversible.\n' + '\n' + ' >>> d = {"one": 1, "two": 2, "three": 3, "four": 4}\n' \ + ' >>> d\n' + " {'one': 1, 'two': 2, 'three': 3, 'four': 4}\n" \ + ' >>> list(reversed(d))\n' + " ['four', 'three', 'two', 'one']\n" + ' >>> list(reversed(d.values()))\n' + ' [4, 3, 2, 1]\n' \ + ' >>> list(reversed(d.items()))\n' + " [('four', 4), ('three', 3), ('two', 2), ('one', 1)]\n" \ + '\n' + ' Changed in version 3.8: Dictionaries are now reversible.\n' + '\n' + 'See also:\n' + '\n' + ' "types.MappingProxyType" can be used to create a read-only ' \ + 'view of a\n' \ + ' "dict".\n' + '\n' + '\n' + 'Dictionary view objects\n' + '=======================\n' + '\n' \ + 'The objects returned by "dict.keys()", "dict.values()" and\n' \ + '"dict.items()" are *view objects*. They provide a dynamic ' \ + 'view on the\n' + 'dictionary’s entries, which means that when the dictionary ' + 'changes,\n' \ + 'the view reflects these changes.\n' \ + '\n' \ + 'Dictionary views can be iterated over to yield their ' + 'respective data,\n' + 'and support membership tests:\n' + '\n' + 'len(dictview)\n' + '\n' + ' Return the number of entries in the dictionary.\n' + '\n' + 'iter(dictview)\n' + '\n' + ' Return an iterator over the keys, values or items ' + '(represented as\n' + ' tuples of "(key, value)") in the dictionary.\n' + '\n' + ' Keys and values are iterated over in insertion order. ' + 'This allows\n' \ + ' the creation of "(value, key)" pairs using "zip()": ' + '"pairs =\n' + ' zip(d.values(), d.keys())". Another way to create the ' + 'same list is\n' \ + ' "pairs = [(v, k) for (k, v) in d.items()]".\n' + '\n' + ' Iterating views while adding or deleting entries in the ' + 'dictionary\n' \ + ' may raise a "RuntimeError" or fail to iterate over all ' + 'entries.\n' \ + '\n' + ' Changed in version 3.7: Dictionary order is guaranteed to ' + 'be\n' + ' insertion order.\n' + '\n' + 'x in dictview\n' \ + '\n' + ' Return "True" if *x* is in the underlying dictionary’s ' \ + 'keys, values\n' + ' or items (in the latter case, *x* should be a "(key, ' + 'value)"\n' + ' tuple).\n' + '\n' \ + 'reversed(dictview)\n' + '\n' \ + ' Return a reverse iterator over the keys, values or items ' \ + 'of the\n' + ' dictionary. The view will be iterated in reverse order of ' \ + 'the\n' + ' insertion.\n' \ + '\n' + ' Changed in version 3.8: Dictionary views are now ' \ + 'reversible.\n' + '\n' + 'dictview.mapping\n' + '\n' + ' Return a "types.MappingProxyType" that wraps the ' + 'original\n' + ' dictionary to which the view refers.\n' + '\n' \ + ' Added in version 3.10.\n' + '\n' \ + 'Keys views are set-like since their entries are unique and ' + '*hashable*.\n' + 'Items views also have set-like operations since the (key, ' + 'value) pairs\n' + 'are unique and the keys are hashable. If all values in an ' + 'items view\n' + 'are hashable as well, then the items view can interoperate ' + 'with other\n' + 'sets. (Values views are not treated as set-like since the ' + 'entries are\n' + 'generally not unique.) For set-like views, all of the ' + 'operations\n' + 'defined for the abstract base class "collections.abc.Set" ' + 'are\n' + 'available (for example, "==", "<", or "^"). While using ' \ + 'set\n' + 'operators, set-like views accept any iterable as the other ' + 'operand,\n' + 'unlike sets which only accept sets as the input.\n' + '\n' + 'An example of dictionary view usage:\n' + '\n' + " >>> dishes = {'eggs': 2, 'sausage': 1, 'bacon': 1, " \ + "'spam': 500}\n" + ' >>> keys = dishes.keys()\n' + ' >>> values = dishes.values()\n' \ + '\n' + ' >>> # iteration\n' + ' >>> n = 0\n' + ' >>> for val in values:\n' \ + ' ... n += val\n' + ' ...\n' + ' >>> print(n)\n' + ' 504\n' \ + '\n' + ' >>> # keys and values are iterated over in the same order ' + '(insertion order)\n' \ + ' >>> list(keys)\n' + " ['eggs', 'sausage', 'bacon', 'spam']\n" \ + ' >>> list(values)\n' + ' [2, 1, 1, 500]\n' \ + '\n' \ + ' >>> # view objects are dynamic and reflect dict changes\n' + " >>> del dishes['eggs']\n" \ + " >>> del dishes['sausage']\n" + ' >>> list(keys)\n' + " ['bacon', 'spam']\n" \ + '\n' + ' >>> # set operations\n' + " >>> keys & {'eggs', 'bacon', 'salad'}\n" + " {'bacon'}\n" + " >>> keys ^ {'sausage', 'juice'} == {'juice', 'sausage', " + "'bacon', 'spam'}\n" + ' True\n' + " >>> keys | ['juice', 'juice', 'juice'] == {'bacon', " \ + "'spam', 'juice'}\n" + ' True\n' + '\n' + ' >>> # get back a read-only proxy for the original ' + 'dictionary\n' + ' >>> values.mapping\n' + " mappingproxy({'bacon': 1, 'spam': 500})\n" + " >>> values.mapping['spam']\n" + ' 500\n', + 'typesmethods': 'Methods\n' + '*******\n' + '\n' + 'Methods are functions that are called using the attribute ' + 'notation.\n' + 'There are two flavors: built-in methods (such as "append()" ' \ + 'on lists)\n' + 'and class instance method. Built-in methods are described ' + 'with the\n' \ + 'types that support them.\n' + '\n' + 'If you access a method (a function defined in a class ' + 'namespace)\n' + 'through an instance, you get a special object: a *bound ' \ + 'method* (also\n' + 'called instance method) object. When called, it will add the ' + '"self"\n' \ + 'argument to the argument list. Bound methods have two ' + 'special read-\n' + 'only attributes: "m.__self__" is the object on which the ' + 'method\n' + 'operates, and "m.__func__" is the function implementing the ' + 'method.\n' + 'Calling "m(arg-1, arg-2, ..., arg-n)" is completely ' \ + 'equivalent to\n' + 'calling "m.__func__(m.__self__, arg-1, arg-2, ..., arg-n)".\n' + '\n' \ + 'Like function objects, bound method objects support getting ' + 'arbitrary\n' \ + 'attributes. However, since method attributes are actually ' + 'stored on\n' + 'the underlying function object ("method.__func__"), setting ' + 'method\n' + 'attributes on bound methods is disallowed. Attempting to ' + 'set an\n' + 'attribute on a method results in an "AttributeError" being ' \ + 'raised. In\n' + 'order to set a method attribute, you need to explicitly set ' + 'it on the\n' + 'underlying function object:\n' + '\n' + ' >>> class C:\n' + ' ... def method(self):\n' + ' ... pass\n' + ' ...\n' + ' >>> c = C()\n' + " >>> c.method.whoami = 'my name is method' # can't set on " + 'the method\n' \ + ' Traceback (most recent call last):\n' + ' File "", line 1, in \n' + " AttributeError: 'method' object has no attribute " + "'whoami'\n" + " >>> c.method.__func__.whoami = 'my name is method'\n" + ' >>> c.method.whoami\n' + " 'my name is method'\n" + '\n' \ + 'See Instance methods for more information.\n', + 'typesmodules': 'Modules\n' + '*******\n' + '\n' + 'The only special operation on a module is attribute access: ' + '"m.name",\n' \ + 'where *m* is a module and *name* accesses a name defined in ' + '*m*’s\n' + 'symbol table. Module attributes can be assigned to. (Note ' + 'that the\n' + '"import" statement is not, strictly speaking, an operation ' + 'on a module\n' + 'object; "import foo" does not require a module object named ' + '*foo* to\n' + 'exist, rather it requires an (external) *definition* for a ' \ + 'module\n' + 'named *foo* somewhere.)\n' + '\n' + 'A special attribute of every module is "__dict__". This is ' + 'the\n' + 'dictionary containing the module’s symbol table. Modifying ' \ + 'this\n' + 'dictionary will actually change the module’s symbol table, ' + 'but direct\n' + 'assignment to the "__dict__" attribute is not possible (you ' + 'can write\n' \ + '"m.__dict__[\'a\'] = 1", which defines "m.a" to be "1", but ' + 'you can’t\n' + 'write "m.__dict__ = {}"). Modifying "__dict__" directly is ' + 'not\n' + 'recommended.\n' + '\n' + 'Modules built into the interpreter are written like this: ' + '"". If loaded from a file, they are ' + 'written as\n' + '"".\n', + 'typesseq': 'Sequence Types — "list", "tuple", "range"\n' + '*****************************************\n' \ + '\n' + 'There are three basic sequence types: lists, tuples, and range\n' + 'objects. Additional sequence types tailored for processing of ' + 'binary\n' + 'data and text strings are described in dedicated sections.\n' + '\n' + '\n' + 'Common Sequence Operations\n' + '==========================\n' \ + '\n' + 'The operations in the following table are supported by most ' + 'sequence\n' + 'types, both mutable and immutable. The ' + '"collections.abc.Sequence" ABC\n' + 'is provided to make it easier to correctly implement these ' + 'operations\n' + 'on custom sequence types.\n' + '\n' + 'This table lists the sequence operations sorted in ascending ' + 'priority.\n' + 'In the table, *s* and *t* are sequences of the same type, *n*, ' + '*i*,\n' + '*j* and *k* are integers and *x* is an arbitrary object that ' + 'meets any\n' + 'type and value restrictions imposed by *s*.\n' + '\n' + 'The "in" and "not in" operations have the same priorities as ' + 'the\n' + 'comparison operations. The "+" (concatenation) and "*" ' + '(repetition)\n' + 'operations have the same priority as the corresponding numeric\n' + 'operations. [3]\n' + '\n' + '+----------------------------+----------------------------------+------------+\n' + '| Operation | Result ' + '| Notes |\n' \ + '|============================|==================================|============|\n' + '| "x in s" | "True" if an item of *s* is ' + '| (1) |\n' + '| | equal to *x*, else "False" ' + '| |\n' + '+----------------------------+----------------------------------+------------+\n' + '| "x not in s" | "False" if an item of *s* is ' + '| (1) |\n' \ + '| | equal to *x*, else "True" ' \ + '| |\n' + '+----------------------------+----------------------------------+------------+\n' + '| "s + t" | the concatenation of *s* and *t* ' + '| (6)(7) |\n' + '+----------------------------+----------------------------------+------------+\n' + '| "s * n" or "n * s" | equivalent to adding *s* to ' + '| (2)(7) |\n' + '| | itself *n* times ' + '| |\n' \ + '+----------------------------+----------------------------------+------------+\n' + '| "s[i]" | *i*th item of *s*, origin 0 ' + '| (3) |\n' \ + '+----------------------------+----------------------------------+------------+\n' + '| "s[i:j]" | slice of *s* from *i* to *j* ' + '| (3)(4) |\n' + '+----------------------------+----------------------------------+------------+\n' \ + '| "s[i:j:k]" | slice of *s* from *i* to *j* ' \ + '| (3)(5) |\n' + '| | with step *k* ' + '| |\n' + '+----------------------------+----------------------------------+------------+\n' + '| "len(s)" | length of *s* ' + '| |\n' \ + '+----------------------------+----------------------------------+------------+\n' + '| "min(s)" | smallest item of *s* ' + '| |\n' \ + '+----------------------------+----------------------------------+------------+\n' \ + '| "max(s)" | largest item of *s* ' \ + '| |\n' + '+----------------------------+----------------------------------+------------+\n' + '| "s.index(x[, i[, j]])" | index of the first occurrence of ' + '| (8) |\n' + '| | *x* in *s* (at or after index ' \ + '| |\n' + '| | *i* and before index *j*) ' + '| |\n' + '+----------------------------+----------------------------------+------------+\n' + '| "s.count(x)" | total number of occurrences of ' + '| |\n' \ + '| | *x* in *s* ' + '| |\n' + '+----------------------------+----------------------------------+------------+\n' + '\n' + 'Sequences of the same type also support comparisons. In ' + 'particular,\n' + 'tuples and lists are compared lexicographically by comparing\n' + 'corresponding elements. This means that to compare equal, every\n' + 'element must compare equal and the two sequences must be of the ' + 'same\n' \ + 'type and have the same length. (For full details see ' + 'Comparisons in\n' + 'the language reference.)\n' + '\n' + 'Forward and reversed iterators over mutable sequences access ' + 'values\n' + 'using an index. That index will continue to march forward (or\n' + 'backward) even if the underlying sequence is mutated. The ' + 'iterator\n' + 'terminates only when an "IndexError" or a "StopIteration" is\n' \ + 'encountered (or when the index drops below zero).\n' + '\n' + 'Notes:\n' \ + '\n' + '1. While the "in" and "not in" operations are used only for ' \ + 'simple\n' + ' containment testing in the general case, some specialised ' + 'sequences\n' + ' (such as "str", "bytes" and "bytearray") also use them for\n' \ + ' subsequence testing:\n' + '\n' + ' >>> "gg" in "eggs"\n' + ' True\n' + '\n' + '2. Values of *n* less than "0" are treated as "0" (which yields ' + 'an\n' + ' empty sequence of the same type as *s*). Note that items in ' + 'the\n' \ + ' sequence *s* are not copied; they are referenced multiple ' + 'times.\n' \ + ' This often haunts new Python programmers; consider:\n' \ + '\n' \ + ' >>> lists = [[]] * 3\n' \ + ' >>> lists\n' \ + ' [[], [], []]\n' + ' >>> lists[0].append(3)\n' + ' >>> lists\n' \ + ' [[3], [3], [3]]\n' + '\n' + ' What has happened is that "[[]]" is a one-element list ' + 'containing\n' + ' an empty list, so all three elements of "[[]] * 3" are ' + 'references\n' \ + ' to this single empty list. Modifying any of the elements of\n' \ + ' "lists" modifies this single list. You can create a list of\n' + ' different lists this way:\n' + '\n' \ + ' >>> lists = [[] for i in range(3)]\n' + ' >>> lists[0].append(3)\n' \ + ' >>> lists[1].append(5)\n' + ' >>> lists[2].append(7)\n' \ + ' >>> lists\n' + ' [[3], [5], [7]]\n' \ + '\n' \ + ' Further explanation is available in the FAQ entry How do I ' \ + 'create a\n' + ' multidimensional list?.\n' + '\n' + '3. If *i* or *j* is negative, the index is relative to the end ' + 'of\n' \ + ' sequence *s*: "len(s) + i" or "len(s) + j" is substituted. ' \ + 'But\n' + ' note that "-0" is still "0".\n' + '\n' + '4. The slice of *s* from *i* to *j* is defined as the sequence ' + 'of\n' + ' items with index *k* such that "i <= k < j". If *i* or *j* ' + 'is\n' \ + ' greater than "len(s)", use "len(s)". If *i* is omitted or ' \ + '"None",\n' + ' use "0". If *j* is omitted or "None", use "len(s)". If *i* ' \ + 'is\n' + ' greater than or equal to *j*, the slice is empty.\n' \ + '\n' + '5. The slice of *s* from *i* to *j* with step *k* is defined as ' \ + 'the\n' + ' sequence of items with index "x = i + n*k" such that "0 <= n ' \ + '<\n' + ' (j-i)/k". In other words, the indices are "i", "i+k", ' \ + '"i+2*k",\n' \ + ' "i+3*k" and so on, stopping when *j* is reached (but never\n' + ' including *j*). When *k* is positive, *i* and *j* are ' \ + 'reduced to\n' + ' "len(s)" if they are greater. When *k* is negative, *i* and ' + '*j* are\n' + ' reduced to "len(s) - 1" if they are greater. If *i* or *j* ' + 'are\n' \ + ' omitted or "None", they become “end” values (which end ' + 'depends on\n' \ + ' the sign of *k*). Note, *k* cannot be zero. If *k* is ' \ + '"None", it\n' + ' is treated like "1".\n' \ + '\n' + '6. Concatenating immutable sequences always results in a new ' + 'object.\n' + ' This means that building up a sequence by repeated ' + 'concatenation\n' + ' will have a quadratic runtime cost in the total sequence ' + 'length.\n' + ' To get a linear runtime cost, you must switch to one of the\n' + ' alternatives below:\n' \ + '\n' \ + ' * if concatenating "str" objects, you can build a list and ' + 'use\n' \ + ' "str.join()" at the end or else write to an "io.StringIO"\n' \ + ' instance and retrieve its value when complete\n' \ + '\n' + ' * if concatenating "bytes" objects, you can similarly use\n' + ' "bytes.join()" or "io.BytesIO", or you can do in-place\n' \ + ' concatenation with a "bytearray" object. "bytearray" ' + 'objects are\n' \ + ' mutable and have an efficient overallocation mechanism\n' \ + '\n' + ' * if concatenating "tuple" objects, extend a "list" instead\n' \ + '\n' + ' * for other types, investigate the relevant class ' + 'documentation\n' + '\n' + '7. Some sequence types (such as "range") only support item ' + 'sequences\n' + ' that follow specific patterns, and hence don’t support ' + 'sequence\n' + ' concatenation or repetition.\n' + '\n' + '8. "index" raises "ValueError" when *x* is not found in *s*. Not ' + 'all\n' + ' implementations support passing the additional arguments *i* ' + 'and\n' \ + ' *j*. These arguments allow efficient searching of subsections ' + 'of\n' + ' the sequence. Passing the extra arguments is roughly ' + 'equivalent to\n' + ' using "s[i:j].index(x)", only without copying any data and ' + 'with the\n' \ + ' returned index being relative to the start of the sequence ' \ + 'rather\n' + ' than the start of the slice.\n' \ + '\n' + '\n' \ + 'Immutable Sequence Types\n' + '========================\n' + '\n' \ + 'The only operation that immutable sequence types generally ' + 'implement\n' + 'that is not also implemented by mutable sequence types is ' + 'support for\n' + 'the "hash()" built-in.\n' + '\n' + 'This support allows immutable sequences, such as "tuple" ' \ + 'instances, to\n' + 'be used as "dict" keys and stored in "set" and "frozenset" ' + 'instances.\n' + '\n' \ + 'Attempting to hash an immutable sequence that contains ' + 'unhashable\n' \ + 'values will result in "TypeError".\n' + '\n' + '\n' + 'Mutable Sequence Types\n' + '======================\n' + '\n' + 'The operations in the following table are defined on mutable ' \ + 'sequence\n' + 'types. The "collections.abc.MutableSequence" ABC is provided to ' + 'make\n' + 'it easier to correctly implement these operations on custom ' + 'sequence\n' \ + 'types.\n' + '\n' + 'In the table *s* is an instance of a mutable sequence type, *t* ' \ + 'is any\n' + 'iterable object and *x* is an arbitrary object that meets any ' + 'type and\n' + 'value restrictions imposed by *s* (for example, "bytearray" ' \ + 'only\n' \ + 'accepts integers that meet the value restriction "0 <= x <= ' + '255").\n' + '\n' + '+--------------------------------+----------------------------------+-----------------------+\n' + '| Operation | ' + 'Result | Notes |\n' \ + '|================================|==================================|=======================|\n' + '| "s[i] = x" | item *i* of *s* is replaced ' + 'by | |\n' \ + '| | ' \ + '*x* | |\n' \ + '+--------------------------------+----------------------------------+-----------------------+\n' + '| "s[i:j] = t" | slice of *s* from *i* to *j* ' + 'is | |\n' \ + '| | replaced by the contents of ' + 'the | |\n' + '| | iterable ' \ + '*t* | |\n' \ + '+--------------------------------+----------------------------------+-----------------------+\n' \ + '| "del s[i:j]" | same as "s[i:j] = ' + '[]" | |\n' + '+--------------------------------+----------------------------------+-----------------------+\n' + '| "s[i:j:k] = t" | the elements of "s[i:j:k]" ' + 'are | (1) |\n' + '| | replaced by those of ' + '*t* | |\n' + '+--------------------------------+----------------------------------+-----------------------+\n' \ + '| "del s[i:j:k]" | removes the elements ' \ + 'of | |\n' + '| | "s[i:j:k]" from the ' \ + 'list | |\n' + '+--------------------------------+----------------------------------+-----------------------+\n' + '| "s.append(x)" | appends *x* to the end of ' \ + 'the | |\n' + '| | sequence (same ' + 'as | |\n' + '| | "s[len(s):len(s)] = ' + '[x]") | |\n' \ + '+--------------------------------+----------------------------------+-----------------------+\n' + '| "s.clear()" | removes all items from *s* ' + '(same | (5) |\n' + '| | as "del ' + 's[:]") | |\n' + '+--------------------------------+----------------------------------+-----------------------+\n' + '| "s.copy()" | creates a shallow copy of ' + '*s* | (5) |\n' + '| | (same as ' + '"s[:]") | |\n' + '+--------------------------------+----------------------------------+-----------------------+\n' + '| "s.extend(t)" or "s += t" | extends *s* with the contents ' + 'of | |\n' \ + '| | *t* (for the most part the ' + 'same | |\n' + '| | as "s[len(s):len(s)] = ' + 't") | |\n' \ + '+--------------------------------+----------------------------------+-----------------------+\n' + '| "s *= n" | updates *s* with its ' \ + 'contents | (6) |\n' + '| | repeated *n* ' + 'times | |\n' \ + '+--------------------------------+----------------------------------+-----------------------+\n' + '| "s.insert(i, x)" | inserts *x* into *s* at ' + 'the | |\n' \ + '| | index given by *i* (same ' + 'as | |\n' + '| | "s[i:i] = ' + '[x]") | |\n' + '+--------------------------------+----------------------------------+-----------------------+\n' + '| "s.pop()" or "s.pop(i)" | retrieves the item at *i* ' + 'and | (2) |\n' + '| | also removes it from ' \ + '*s* | |\n' + '+--------------------------------+----------------------------------+-----------------------+\n' + '| "s.remove(x)" | removes the first item from ' + '*s* | (3) |\n' + '| | where "s[i]" is equal to ' + '*x* | |\n' + '+--------------------------------+----------------------------------+-----------------------+\n' + '| "s.reverse()" | reverses the items of *s* ' + 'in | (4) |\n' + '| | ' + 'place | |\n' + '+--------------------------------+----------------------------------+-----------------------+\n' + '\n' + 'Notes:\n' \ + '\n' + '1. If *k* is not equal to "1", *t* must have the same length as ' + 'the\n' + ' slice it is replacing.\n' + '\n' + '2. The optional argument *i* defaults to "-1", so that by ' + 'default the\n' + ' last item is removed and returned.\n' + '\n' \ + '3. "remove()" raises "ValueError" when *x* is not found in *s*.\n' + '\n' + '4. The "reverse()" method modifies the sequence in place for ' \ + 'economy\n' + ' of space when reversing a large sequence. To remind users ' + 'that it\n' + ' operates by side effect, it does not return the reversed ' \ + 'sequence.\n' + '\n' \ + '5. "clear()" and "copy()" are included for consistency with the\n' + ' interfaces of mutable containers that don’t support slicing\n' + ' operations (such as "dict" and "set"). "copy()" is not part ' \ + 'of the\n' \ + ' "collections.abc.MutableSequence" ABC, but most concrete ' \ + 'mutable\n' \ + ' sequence classes provide it.\n' + '\n' + ' Added in version 3.3: "clear()" and "copy()" methods.\n' + '\n' + '6. The value *n* is an integer, or an object implementing\n' + ' "__index__()". Zero and negative values of *n* clear the ' + 'sequence.\n' \ + ' Items in the sequence are not copied; they are referenced ' \ + 'multiple\n' + ' times, as explained for "s * n" under Common Sequence ' + 'Operations.\n' + '\n' \ + '\n' + 'Lists\n' + '=====\n' + '\n' + 'Lists are mutable sequences, typically used to store collections ' + 'of\n' + 'homogeneous items (where the precise degree of similarity will ' + 'vary by\n' \ + 'application).\n' + '\n' + 'class list([iterable])\n' \ + '\n' + ' Lists may be constructed in several ways:\n' \ + '\n' + ' * Using a pair of square brackets to denote the empty list: ' + '"[]"\n' + '\n' + ' * Using square brackets, separating items with commas: "[a]", ' + '"[a,\n' + ' b, c]"\n' + '\n' + ' * Using a list comprehension: "[x for x in iterable]"\n' + '\n' + ' * Using the type constructor: "list()" or "list(iterable)"\n' + '\n' + ' The constructor builds a list whose items are the same and in ' + 'the\n' + ' same order as *iterable*’s items. *iterable* may be either ' + 'a\n' + ' sequence, a container that supports iteration, or an ' + 'iterator\n' + ' object. If *iterable* is already a list, a copy is made and\n' + ' returned, similar to "iterable[:]". For example, ' + '"list(\'abc\')"\n' + ' returns "[\'a\', \'b\', \'c\']" and "list( (1, 2, 3) )" ' + 'returns "[1, 2,\n' \ + ' 3]". If no argument is given, the constructor creates a new ' + 'empty\n' + ' list, "[]".\n' + '\n' + ' Many other operations also produce lists, including the ' + '"sorted()"\n' + ' built-in.\n' \ + '\n' + ' Lists implement all of the common and mutable sequence ' \ + 'operations.\n' + ' Lists also provide the following additional method:\n' + '\n' + ' sort(*, key=None, reverse=False)\n' \ + '\n' + ' This method sorts the list in place, using only "<" ' + 'comparisons\n' + ' between items. Exceptions are not suppressed - if any ' + 'comparison\n' + ' operations fail, the entire sort operation will fail (and ' + 'the\n' + ' list will likely be left in a partially modified state).\n' \ + '\n' + ' "sort()" accepts two arguments that can only be passed by\n' + ' keyword (keyword-only arguments):\n' + '\n' \ + ' *key* specifies a function of one argument that is used ' + 'to\n' + ' extract a comparison key from each list element (for ' + 'example,\n' + ' "key=str.lower"). The key corresponding to each item in ' + 'the list\n' + ' is calculated once and then used for the entire sorting ' \ + 'process.\n' + ' The default value of "None" means that list items are ' + 'sorted\n' \ + ' directly without calculating a separate key value.\n' + '\n' + ' The "functools.cmp_to_key()" utility is available to ' + 'convert a\n' + ' 2.x style *cmp* function to a *key* function.\n' + '\n' + ' *reverse* is a boolean value. If set to "True", then the ' + 'list\n' + ' elements are sorted as if each comparison were reversed.\n' + '\n' + ' This method modifies the sequence in place for economy of ' + 'space\n' + ' when sorting a large sequence. To remind users that it ' \ + 'operates\n' + ' by side effect, it does not return the sorted sequence ' + '(use\n' \ + ' "sorted()" to explicitly request a new sorted list ' + 'instance).\n' + '\n' + ' The "sort()" method is guaranteed to be stable. A sort ' + 'is\n' + ' stable if it guarantees not to change the relative order ' + 'of\n' + ' elements that compare equal — this is helpful for sorting ' \ + 'in\n' + ' multiple passes (for example, sort by department, then by ' + 'salary\n' \ + ' grade).\n' + '\n' + ' For sorting examples and a brief sorting tutorial, see ' + 'Sorting\n' + ' Techniques.\n' + '\n' + ' **CPython implementation detail:** While a list is being ' + 'sorted,\n' + ' the effect of attempting to mutate, or even inspect, the ' + 'list is\n' \ + ' undefined. The C implementation of Python makes the list ' + 'appear\n' + ' empty for the duration, and raises "ValueError" if it can ' + 'detect\n' + ' that the list has been mutated during a sort.\n' + '\n' + '\n' + 'Tuples\n' + '======\n' + '\n' + 'Tuples are immutable sequences, typically used to store ' + 'collections of\n' + 'heterogeneous data (such as the 2-tuples produced by the ' + '"enumerate()"\n' + 'built-in). Tuples are also used for cases where an immutable ' + 'sequence\n' + 'of homogeneous data is needed (such as allowing storage in a ' + '"set" or\n' + '"dict" instance).\n' + '\n' + 'class tuple([iterable])\n' + '\n' + ' Tuples may be constructed in a number of ways:\n' + '\n' + ' * Using a pair of parentheses to denote the empty tuple: ' + '"()"\n' + '\n' + ' * Using a trailing comma for a singleton tuple: "a," or ' \ + '"(a,)"\n' + '\n' + ' * Separating items with commas: "a, b, c" or "(a, b, c)"\n' + '\n' \ + ' * Using the "tuple()" built-in: "tuple()" or ' + '"tuple(iterable)"\n' + '\n' + ' The constructor builds a tuple whose items are the same and ' + 'in the\n' + ' same order as *iterable*’s items. *iterable* may be either ' + 'a\n' + ' sequence, a container that supports iteration, or an ' + 'iterator\n' + ' object. If *iterable* is already a tuple, it is returned\n' + ' unchanged. For example, "tuple(\'abc\')" returns "(\'a\', ' + '\'b\', \'c\')"\n' + ' and "tuple( [1, 2, 3] )" returns "(1, 2, 3)". If no argument ' \ + 'is\n' + ' given, the constructor creates a new empty tuple, "()".\n' + '\n' \ + ' Note that it is actually the comma which makes a tuple, not ' + 'the\n' + ' parentheses. The parentheses are optional, except in the ' + 'empty\n' + ' tuple case, or when they are needed to avoid syntactic ' \ + 'ambiguity.\n' + ' For example, "f(a, b, c)" is a function call with three ' + 'arguments,\n' + ' while "f((a, b, c))" is a function call with a 3-tuple as the ' + 'sole\n' + ' argument.\n' \ + '\n' + ' Tuples implement all of the common sequence operations.\n' + '\n' + 'For heterogeneous collections of data where access by name is ' + 'clearer\n' + 'than access by index, "collections.namedtuple()" may be a more\n' + 'appropriate choice than a simple tuple object.\n' \ + '\n' + '\n' + 'Ranges\n' + '======\n' + '\n' + 'The "range" type represents an immutable sequence of numbers and ' \ + 'is\n' \ + 'commonly used for looping a specific number of times in "for" ' \ + 'loops.\n' + '\n' + 'class range(stop)\n' + 'class range(start, stop[, step])\n' + '\n' + ' The arguments to the range constructor must be integers ' \ + '(either\n' + ' built-in "int" or any object that implements the ' \ + '"__index__()"\n' + ' special method). If the *step* argument is omitted, it ' + 'defaults to\n' + ' "1". If the *start* argument is omitted, it defaults to "0". ' + 'If\n' \ + ' *step* is zero, "ValueError" is raised.\n' + '\n' \ + ' For a positive *step*, the contents of a range "r" are ' + 'determined\n' \ + ' by the formula "r[i] = start + step*i" where "i >= 0" and ' + '"r[i] <\n' \ + ' stop".\n' + '\n' + ' For a negative *step*, the contents of the range are still\n' + ' determined by the formula "r[i] = start + step*i", but the\n' + ' constraints are "i >= 0" and "r[i] > stop".\n' \ + '\n' + ' A range object will be empty if "r[0]" does not meet the ' + 'value\n' + ' constraint. Ranges do support negative indices, but these ' + 'are\n' + ' interpreted as indexing from the end of the sequence ' + 'determined by\n' + ' the positive indices.\n' + '\n' + ' Ranges containing absolute values larger than "sys.maxsize" ' + 'are\n' + ' permitted but some features (such as "len()") may raise\n' + ' "OverflowError".\n' + '\n' \ + ' Range examples:\n' + '\n' + ' >>> list(range(10))\n' \ + ' [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]\n' + ' >>> list(range(1, 11))\n' + ' [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]\n' \ + ' >>> list(range(0, 30, 5))\n' + ' [0, 5, 10, 15, 20, 25]\n' \ + ' >>> list(range(0, 10, 3))\n' + ' [0, 3, 6, 9]\n' \ + ' >>> list(range(0, -10, -1))\n' + ' [0, -1, -2, -3, -4, -5, -6, -7, -8, -9]\n' \ + ' >>> list(range(0))\n' + ' []\n' + ' >>> list(range(1, 0))\n' \ + ' []\n' + '\n' + ' Ranges implement all of the common sequence operations ' \ + 'except\n' \ + ' concatenation and repetition (due to the fact that range ' \ + 'objects\n' \ + ' can only represent sequences that follow a strict pattern ' \ + 'and\n' \ + ' repetition and concatenation will usually violate that ' + 'pattern).\n' + '\n' \ + ' start\n' + '\n' + ' The value of the *start* parameter (or "0" if the ' + 'parameter was\n' + ' not supplied)\n' \ + '\n' + ' stop\n' + '\n' \ + ' The value of the *stop* parameter\n' \ + '\n' + ' step\n' + '\n' + ' The value of the *step* parameter (or "1" if the parameter ' + 'was\n' + ' not supplied)\n' + '\n' + 'The advantage of the "range" type over a regular "list" or ' + '"tuple" is\n' + 'that a "range" object will always take the same (small) amount ' \ + 'of\n' + 'memory, no matter the size of the range it represents (as it ' + 'only\n' + 'stores the "start", "stop" and "step" values, calculating ' \ + 'individual\n' + 'items and subranges as needed).\n' + '\n' \ + 'Range objects implement the "collections.abc.Sequence" ABC, and\n' + 'provide features such as containment tests, element index ' \ + 'lookup,\n' \ + 'slicing and support for negative indices (see Sequence Types — ' + 'list,\n' \ + 'tuple, range):\n' + '\n' + '>>> r = range(0, 20, 2)\n' + '>>> r\n' + 'range(0, 20, 2)\n' \ + '>>> 11 in r\n' \ + 'False\n' \ + '>>> 10 in r\n' \ + 'True\n' \ + '>>> r.index(10)\n' + '5\n' + '>>> r[5]\n' \ + '10\n' + '>>> r[:5]\n' + 'range(0, 10, 2)\n' + '>>> r[-1]\n' + '18\n' + '\n' + 'Testing range objects for equality with "==" and "!=" compares ' + 'them as\n' + 'sequences. That is, two range objects are considered equal if ' + 'they\n' \ + 'represent the same sequence of values. (Note that two range ' + 'objects\n' \ + 'that compare equal might have different "start", "stop" and ' + '"step"\n' + 'attributes, for example "range(0) == range(2, 1, 3)" or ' \ + '"range(0, 3,\n' + '2) == range(0, 4, 2)".)\n' \ + '\n' + 'Changed in version 3.2: Implement the Sequence ABC. Support ' \ + 'slicing\n' + 'and negative indices. Test "int" objects for membership in ' + 'constant\n' \ + 'time instead of iterating through all items.\n' + '\n' + 'Changed in version 3.3: Define ‘==’ and ‘!=’ to compare range ' + 'objects\n' + 'based on the sequence of values they define (instead of ' \ + 'comparing\n' + 'based on object identity).Added the "start", "stop" and "step"\n' + 'attributes.\n' \ + '\n' + 'See also:\n' + '\n' + ' * The linspace recipe shows how to implement a lazy version of ' \ + 'range\n' + ' suitable for floating-point applications.\n', + 'typesseq-mutable': 'Mutable Sequence Types\n' + '**********************\n' + '\n' + 'The operations in the following table are defined on ' + 'mutable sequence\n' + 'types. The "collections.abc.MutableSequence" ABC is ' + 'provided to make\n' + 'it easier to correctly implement these operations on ' \ + 'custom sequence\n' + 'types.\n' + '\n' + 'In the table *s* is an instance of a mutable sequence ' + 'type, *t* is any\n' + 'iterable object and *x* is an arbitrary object that ' + 'meets any type and\n' + 'value restrictions imposed by *s* (for example, ' + '"bytearray" only\n' + 'accepts integers that meet the value restriction "0 <= x ' \ + '<= 255").\n' + '\n' + '+--------------------------------+----------------------------------+-----------------------+\n' + '| Operation | ' \ + 'Result | Notes ' + '|\n' + '|================================|==================================|=======================|\n' + '| "s[i] = x" | item *i* of *s* is ' + 'replaced by | |\n' + '| | ' + '*x* | ' + '|\n' \ + '+--------------------------------+----------------------------------+-----------------------+\n' + '| "s[i:j] = t" | slice of *s* from *i* ' + 'to *j* is | |\n' \ + '| | replaced by the ' + 'contents of the | |\n' + '| | iterable ' + '*t* | |\n' + '+--------------------------------+----------------------------------+-----------------------+\n' \ + '| "del s[i:j]" | same as "s[i:j] = ' + '[]" | |\n' + '+--------------------------------+----------------------------------+-----------------------+\n' + '| "s[i:j:k] = t" | the elements of ' + '"s[i:j:k]" are | (1) |\n' + '| | replaced by those of ' + '*t* | |\n' + '+--------------------------------+----------------------------------+-----------------------+\n' + '| "del s[i:j:k]" | removes the elements ' + 'of | |\n' + '| | "s[i:j:k]" from the ' + 'list | |\n' + '+--------------------------------+----------------------------------+-----------------------+\n' + '| "s.append(x)" | appends *x* to the ' + 'end of the | |\n' + '| | sequence (same ' + 'as | |\n' + '| | "s[len(s):len(s)] = ' \ + '[x]") | |\n' + '+--------------------------------+----------------------------------+-----------------------+\n' + '| "s.clear()" | removes all items ' \ + 'from *s* (same | (5) |\n' + '| | as "del ' \ + 's[:]") | |\n' + '+--------------------------------+----------------------------------+-----------------------+\n' + '| "s.copy()" | creates a shallow ' + 'copy of *s* | (5) |\n' + '| | (same as ' + '"s[:]") | |\n' + '+--------------------------------+----------------------------------+-----------------------+\n' + '| "s.extend(t)" or "s += t" | extends *s* with the ' + 'contents of | |\n' + '| | *t* (for the most ' + 'part the same | |\n' + '| | as "s[len(s):len(s)] ' + '= t") | |\n' + '+--------------------------------+----------------------------------+-----------------------+\n' + '| "s *= n" | updates *s* with its ' + 'contents | (6) |\n' \ + '| | repeated *n* ' + 'times | |\n' \ + '+--------------------------------+----------------------------------+-----------------------+\n' + '| "s.insert(i, x)" | inserts *x* into *s* ' + 'at the | |\n' \ + '| | index given by *i* ' + '(same as | |\n' \ + '| | "s[i:i] = ' + '[x]") | |\n' + '+--------------------------------+----------------------------------+-----------------------+\n' \ + '| "s.pop()" or "s.pop(i)" | retrieves the item at ' + '*i* and | (2) |\n' + '| | also removes it from ' + '*s* | |\n' + '+--------------------------------+----------------------------------+-----------------------+\n' + '| "s.remove(x)" | removes the first ' + 'item from *s* | (3) |\n' + '| | where "s[i]" is equal ' \ + 'to *x* | |\n' + '+--------------------------------+----------------------------------+-----------------------+\n' \ + '| "s.reverse()" | reverses the items of ' \ + '*s* in | (4) |\n' + '| | ' + 'place | ' \ + '|\n' + '+--------------------------------+----------------------------------+-----------------------+\n' + '\n' + 'Notes:\n' + '\n' + '1. If *k* is not equal to "1", *t* must have the same ' + 'length as the\n' + ' slice it is replacing.\n' + '\n' + '2. The optional argument *i* defaults to "-1", so that ' + 'by default the\n' \ + ' last item is removed and returned.\n' + '\n' \ + '3. "remove()" raises "ValueError" when *x* is not found ' + 'in *s*.\n' \ + '\n' \ + '4. The "reverse()" method modifies the sequence in place ' \ + 'for economy\n' \ + ' of space when reversing a large sequence. To remind ' + 'users that it\n' + ' operates by side effect, it does not return the ' + 'reversed sequence.\n' \ + '\n' + '5. "clear()" and "copy()" are included for consistency ' \ + 'with the\n' + ' interfaces of mutable containers that don’t support ' + 'slicing\n' + ' operations (such as "dict" and "set"). "copy()" is ' \ + 'not part of the\n' + ' "collections.abc.MutableSequence" ABC, but most ' + 'concrete mutable\n' \ + ' sequence classes provide it.\n' + '\n' \ + ' Added in version 3.3: "clear()" and "copy()" ' + 'methods.\n' \ + '\n' \ + '6. The value *n* is an integer, or an object ' \ + 'implementing\n' + ' "__index__()". Zero and negative values of *n* clear ' + 'the sequence.\n' \ + ' Items in the sequence are not copied; they are ' + 'referenced multiple\n' \ + ' times, as explained for "s * n" under Common Sequence ' \ + 'Operations.\n', + 'unary': 'Unary arithmetic and bitwise operations\n' + '***************************************\n' '\n' - 'str.ljust(width[, fillchar])\n' + 'All unary arithmetic and bitwise operations have the same ' + 'priority:\n' '\n' - ' Return the string left justified in a string of length ' - '*width*.\n' - ' Padding is done using the specified *fillchar* (default ' - 'is an ASCII\n' - ' space). The original string is returned if *width* is ' - 'less than or\n' - ' equal to "len(s)".\n' + ' u_expr ::= power | "-" u_expr | "+" u_expr | "~" u_expr\n' '\n' - 'str.lower()\n' + 'The unary "-" (minus) operator yields the negation of its numeric\n' + 'argument; the operation can be overridden with the "__neg__()" ' + 'special\n' + 'method.\n' '\n' - ' Return a copy of the string with all the cased ' - 'characters [4]\n' - ' converted to lowercase.\n' + 'The unary "+" (plus) operator yields its numeric argument ' + 'unchanged;\n' + 'the operation can be overridden with the "__pos__()" special ' + 'method.\n' '\n' - ' The lowercasing algorithm used is described in section ' - '3.13 of the\n' - ' Unicode Standard.\n' + 'The unary "~" (invert) operator yields the bitwise inversion of ' + 'its\n' + 'integer argument. The bitwise inversion of "x" is defined as\n' \ + '"-(x+1)". It only applies to integral numbers or to custom ' + 'objects\n' + 'that override the "__invert__()" special method.\n' \ '\n' - 'str.lstrip([chars])\n' + 'In all three cases, if the argument does not have the proper type, ' + 'a\n' + '"TypeError" exception is raised.\n', + 'while': 'The "while" statement\n' + '*********************\n' '\n' - ' Return a copy of the string with leading characters ' - 'removed. The\n' - ' *chars* argument is a string specifying the set of ' - 'characters to be\n' - ' removed. If omitted or "None", the *chars* argument ' - 'defaults to\n' - ' removing whitespace. The *chars* argument is not a ' - 'prefix; rather,\n' - ' all combinations of its values are stripped:\n' + 'The "while" statement is used for repeated execution as long as an\n' + 'expression is true:\n' \ '\n' - " >>> ' spacious '.lstrip()\n" - " 'spacious '\n" - " >>> 'www.example.com'.lstrip('cmowz.')\n" - " 'example.com'\n" + ' while_stmt ::= "while" assignment_expression ":" suite\n' \ + ' ["else" ":" suite]\n' '\n' - 'static str.maketrans(x[, y[, z]])\n' + 'This repeatedly tests the expression and, if it is true, executes ' + 'the\n' + 'first suite; if the expression is false (which may be the first ' + 'time\n' \ + 'it is tested) the suite of the "else" clause, if present, is ' + 'executed\n' \ + 'and the loop terminates.\n' '\n' - ' This static method returns a translation table usable ' - 'for\n' - ' "str.translate()".\n' - '\n' - ' If there is only one argument, it must be a dictionary ' - 'mapping\n' - ' Unicode ordinals (integers) or characters (strings of ' - 'length 1) to\n' - ' Unicode ordinals, strings (of arbitrary lengths) or ' - '"None".\n' - ' Character keys will then be converted to ordinals.\n' - '\n' - ' If there are two arguments, they must be strings of ' - 'equal length,\n' - ' and in the resulting dictionary, each character in x ' - 'will be mapped\n' - ' to the character at the same position in y. If there ' - 'is a third\n' - ' argument, it must be a string, whose characters will be ' - 'mapped to\n' - ' "None" in the result.\n' - '\n' - 'str.partition(sep)\n' - '\n' - ' Split the string at the first occurrence of *sep*, and ' - 'return a\n' - ' 3-tuple containing the part before the separator, the ' - 'separator\n' - ' itself, and the part after the separator. If the ' - 'separator is not\n' - ' found, return a 3-tuple containing the string itself, ' - 'followed by\n' - ' two empty strings.\n' - '\n' - 'str.replace(old, new[, count])\n' - '\n' - ' Return a copy of the string with all occurrences of ' - 'substring *old*\n' - ' replaced by *new*. If the optional argument *count* is ' - 'given, only\n' - ' the first *count* occurrences are replaced.\n' - '\n' - 'str.rfind(sub[, start[, end]])\n' - '\n' - ' Return the highest index in the string where substring ' - '*sub* is\n' - ' found, such that *sub* is contained within ' - '"s[start:end]".\n' - ' Optional arguments *start* and *end* are interpreted as ' - 'in slice\n' - ' notation. Return "-1" on failure.\n' - '\n' - 'str.rindex(sub[, start[, end]])\n' - '\n' - ' Like "rfind()" but raises "ValueError" when the ' - 'substring *sub* is\n' - ' not found.\n' - '\n' - 'str.rjust(width[, fillchar])\n' - '\n' - ' Return the string right justified in a string of length ' - '*width*.\n' - ' Padding is done using the specified *fillchar* (default ' - 'is an ASCII\n' - ' space). The original string is returned if *width* is ' - 'less than or\n' - ' equal to "len(s)".\n' - '\n' - 'str.rpartition(sep)\n' - '\n' - ' Split the string at the last occurrence of *sep*, and ' - 'return a\n' - ' 3-tuple containing the part before the separator, the ' - 'separator\n' - ' itself, and the part after the separator. If the ' - 'separator is not\n' - ' found, return a 3-tuple containing two empty strings, ' - 'followed by\n' - ' the string itself.\n' - '\n' - 'str.rsplit(sep=None, maxsplit=-1)\n' - '\n' - ' Return a list of the words in the string, using *sep* ' - 'as the\n' - ' delimiter string. If *maxsplit* is given, at most ' - '*maxsplit* splits\n' - ' are done, the *rightmost* ones. If *sep* is not ' - 'specified or\n' - ' "None", any whitespace string is a separator. Except ' - 'for splitting\n' - ' from the right, "rsplit()" behaves like "split()" which ' - 'is\n' - ' described in detail below.\n' - '\n' - 'str.rstrip([chars])\n' - '\n' - ' Return a copy of the string with trailing characters ' - 'removed. The\n' - ' *chars* argument is a string specifying the set of ' - 'characters to be\n' - ' removed. If omitted or "None", the *chars* argument ' - 'defaults to\n' - ' removing whitespace. The *chars* argument is not a ' - 'suffix; rather,\n' - ' all combinations of its values are stripped:\n' - '\n' - " >>> ' spacious '.rstrip()\n" - " ' spacious'\n" - " >>> 'mississippi'.rstrip('ipz')\n" - " 'mississ'\n" - '\n' - 'str.split(sep=None, maxsplit=-1)\n' - '\n' - ' Return a list of the words in the string, using *sep* ' - 'as the\n' - ' delimiter string. If *maxsplit* is given, at most ' - '*maxsplit*\n' - ' splits are done (thus, the list will have at most ' - '"maxsplit+1"\n' - ' elements). If *maxsplit* is not specified or "-1", ' - 'then there is\n' - ' no limit on the number of splits (all possible splits ' - 'are made).\n' - '\n' - ' If *sep* is given, consecutive delimiters are not ' - 'grouped together\n' - ' and are deemed to delimit empty strings (for example,\n' - ' "\'1,,2\'.split(\',\')" returns "[\'1\', \'\', ' - '\'2\']"). The *sep* argument\n' - ' may consist of multiple characters (for example,\n' - ' "\'1<>2<>3\'.split(\'<>\')" returns "[\'1\', \'2\', ' - '\'3\']"). Splitting an\n' - ' empty string with a specified separator returns ' - '"[\'\']".\n' - '\n' - ' For example:\n' - '\n' - " >>> '1,2,3'.split(',')\n" - " ['1', '2', '3']\n" - " >>> '1,2,3'.split(',', maxsplit=1)\n" - " ['1', '2,3']\n" - " >>> '1,2,,3,'.split(',')\n" - " ['1', '2', '', '3', '']\n" - '\n' - ' If *sep* is not specified or is "None", a different ' - 'splitting\n' - ' algorithm is applied: runs of consecutive whitespace ' - 'are regarded\n' - ' as a single separator, and the result will contain no ' - 'empty strings\n' - ' at the start or end if the string has leading or ' - 'trailing\n' - ' whitespace. Consequently, splitting an empty string or ' - 'a string\n' - ' consisting of just whitespace with a "None" separator ' - 'returns "[]".\n' - '\n' - ' For example:\n' - '\n' - " >>> '1 2 3'.split()\n" - " ['1', '2', '3']\n" - " >>> '1 2 3'.split(maxsplit=1)\n" - " ['1', '2 3']\n" - " >>> ' 1 2 3 '.split()\n" - " ['1', '2', '3']\n" - '\n' - 'str.splitlines([keepends])\n' - '\n' - ' Return a list of the lines in the string, breaking at ' - 'line\n' - ' boundaries. Line breaks are not included in the ' - 'resulting list\n' - ' unless *keepends* is given and true.\n' - '\n' - ' This method splits on the following line boundaries. ' - 'In\n' - ' particular, the boundaries are a superset of *universal ' - 'newlines*.\n' - '\n' - ' ' - '+-------------------------+-------------------------------+\n' - ' | Representation | ' - 'Description |\n' - ' ' - '+=========================+===============================+\n' - ' | "\\n" | Line ' - 'Feed |\n' - ' ' - '+-------------------------+-------------------------------+\n' - ' | "\\r" | Carriage ' - 'Return |\n' - ' ' - '+-------------------------+-------------------------------+\n' - ' | "\\r\\n" | Carriage Return + Line ' - 'Feed |\n' - ' ' - '+-------------------------+-------------------------------+\n' - ' | "\\v" or "\\x0b" | Line ' - 'Tabulation |\n' - ' ' - '+-------------------------+-------------------------------+\n' - ' | "\\f" or "\\x0c" | Form ' - 'Feed |\n' - ' ' - '+-------------------------+-------------------------------+\n' - ' | "\\x1c" | File ' - 'Separator |\n' - ' ' - '+-------------------------+-------------------------------+\n' - ' | "\\x1d" | Group ' - 'Separator |\n' - ' ' - '+-------------------------+-------------------------------+\n' - ' | "\\x1e" | Record ' - 'Separator |\n' - ' ' - '+-------------------------+-------------------------------+\n' - ' | "\\x85" | Next Line (C1 Control ' - 'Code) |\n' - ' ' - '+-------------------------+-------------------------------+\n' - ' | "\\u2028" | Line ' - 'Separator |\n' - ' ' - '+-------------------------+-------------------------------+\n' - ' | "\\u2029" | Paragraph ' - 'Separator |\n' - ' ' - '+-------------------------+-------------------------------+\n' - '\n' - ' Changed in version 3.2: "\\v" and "\\f" added to list ' - 'of line\n' - ' boundaries.\n' - '\n' - ' For example:\n' - '\n' - " >>> 'ab c\\n\\nde fg\\rkl\\r\\n'.splitlines()\n" - " ['ab c', '', 'de fg', 'kl']\n" - " >>> 'ab c\\n\\nde " - "fg\\rkl\\r\\n'.splitlines(keepends=True)\n" - " ['ab c\\n', '\\n', 'de fg\\r', 'kl\\r\\n']\n" - '\n' - ' Unlike "split()" when a delimiter string *sep* is ' - 'given, this\n' - ' method returns an empty list for the empty string, and ' - 'a terminal\n' - ' line break does not result in an extra line:\n' - '\n' - ' >>> "".splitlines()\n' - ' []\n' - ' >>> "One line\\n".splitlines()\n' - " ['One line']\n" - '\n' - ' For comparison, "split(\'\\n\')" gives:\n' - '\n' - " >>> ''.split('\\n')\n" - " ['']\n" - " >>> 'Two lines\\n'.split('\\n')\n" - " ['Two lines', '']\n" - '\n' - 'str.startswith(prefix[, start[, end]])\n' - '\n' - ' Return "True" if string starts with the *prefix*, ' - 'otherwise return\n' - ' "False". *prefix* can also be a tuple of prefixes to ' - 'look for.\n' - ' With optional *start*, test string beginning at that ' - 'position.\n' - ' With optional *end*, stop comparing string at that ' - 'position.\n' - '\n' - 'str.strip([chars])\n' - '\n' - ' Return a copy of the string with the leading and ' - 'trailing\n' - ' characters removed. The *chars* argument is a string ' - 'specifying the\n' - ' set of characters to be removed. If omitted or "None", ' - 'the *chars*\n' - ' argument defaults to removing whitespace. The *chars* ' - 'argument is\n' - ' not a prefix or suffix; rather, all combinations of its ' - 'values are\n' - ' stripped:\n' - '\n' - " >>> ' spacious '.strip()\n" - " 'spacious'\n" - " >>> 'www.example.com'.strip('cmowz.')\n" - " 'example'\n" - '\n' - ' The outermost leading and trailing *chars* argument ' - 'values are\n' - ' stripped from the string. Characters are removed from ' - 'the leading\n' - ' end until reaching a string character that is not ' - 'contained in the\n' - ' set of characters in *chars*. A similar action takes ' - 'place on the\n' - ' trailing end. For example:\n' - '\n' - " >>> comment_string = '#....... Section 3.2.1 Issue " - "#32 .......'\n" - " >>> comment_string.strip('.#! ')\n" - " 'Section 3.2.1 Issue #32'\n" - '\n' - 'str.swapcase()\n' - '\n' - ' Return a copy of the string with uppercase characters ' - 'converted to\n' - ' lowercase and vice versa. Note that it is not ' - 'necessarily true that\n' - ' "s.swapcase().swapcase() == s".\n' - '\n' - 'str.title()\n' - '\n' - ' Return a titlecased version of the string where words ' - 'start with an\n' - ' uppercase character and the remaining characters are ' - 'lowercase.\n' - '\n' - ' For example:\n' - '\n' - " >>> 'Hello world'.title()\n" - " 'Hello World'\n" - '\n' - ' The algorithm uses a simple language-independent ' - 'definition of a\n' - ' word as groups of consecutive letters. The definition ' - 'works in\n' - ' many contexts but it means that apostrophes in ' - 'contractions and\n' - ' possessives form word boundaries, which may not be the ' - 'desired\n' - ' result:\n' - '\n' - ' >>> "they\'re bill\'s friends from the UK".title()\n' - ' "They\'Re Bill\'S Friends From The Uk"\n' - '\n' - ' A workaround for apostrophes can be constructed using ' - 'regular\n' - ' expressions:\n' - '\n' - ' >>> import re\n' - ' >>> def titlecase(s):\n' - ' ... return re.sub(r"[A-Za-z]+(\'[A-Za-z]+)?",\n' - ' ... lambda mo: ' - 'mo.group(0)[0].upper() +\n' - ' ... ' - 'mo.group(0)[1:].lower(),\n' - ' ... s)\n' - ' ...\n' - ' >>> titlecase("they\'re bill\'s friends.")\n' - ' "They\'re Bill\'s Friends."\n' - '\n' - 'str.translate(table)\n' - '\n' - ' Return a copy of the string in which each character has ' - 'been mapped\n' - ' through the given translation table. The table must be ' - 'an object\n' - ' that implements indexing via "__getitem__()", typically ' - 'a *mapping*\n' - ' or *sequence*. When indexed by a Unicode ordinal (an ' - 'integer), the\n' - ' table object can do any of the following: return a ' - 'Unicode ordinal\n' - ' or a string, to map the character to one or more other ' - 'characters;\n' - ' return "None", to delete the character from the return ' - 'string; or\n' - ' raise a "LookupError" exception, to map the character ' - 'to itself.\n' - '\n' - ' You can use "str.maketrans()" to create a translation ' - 'map from\n' - ' character-to-character mappings in different formats.\n' - '\n' - ' See also the "codecs" module for a more flexible ' - 'approach to custom\n' - ' character mappings.\n' - '\n' - 'str.upper()\n' - '\n' - ' Return a copy of the string with all the cased ' - 'characters [4]\n' - ' converted to uppercase. Note that ' - '"s.upper().isupper()" might be\n' - ' "False" if "s" contains uncased characters or if the ' - 'Unicode\n' - ' category of the resulting character(s) is not “Lu” ' - '(Letter,\n' - ' uppercase), but e.g. “Lt” (Letter, titlecase).\n' - '\n' - ' The uppercasing algorithm used is described in section ' - '3.13 of the\n' - ' Unicode Standard.\n' - '\n' - 'str.zfill(width)\n' - '\n' - ' Return a copy of the string left filled with ASCII ' - '"\'0\'" digits to\n' - ' make a string of length *width*. A leading sign prefix\n' - ' ("\'+\'"/"\'-\'") is handled by inserting the padding ' - '*after* the sign\n' - ' character rather than before. The original string is ' - 'returned if\n' - ' *width* is less than or equal to "len(s)".\n' - '\n' - ' For example:\n' - '\n' - ' >>> "42".zfill(5)\n' - " '00042'\n" - ' >>> "-42".zfill(5)\n' - " '-0042'\n", - 'strings': 'String and Bytes literals\n' - '*************************\n' - '\n' - 'String literals are described by the following lexical ' - 'definitions:\n' - '\n' - ' stringliteral ::= [stringprefix](shortstring | longstring)\n' - ' stringprefix ::= "r" | "u" | "R" | "U" | "f" | "F"\n' - ' | "fr" | "Fr" | "fR" | "FR" | "rf" | "rF" | ' - '"Rf" | "RF"\n' - ' shortstring ::= "\'" shortstringitem* "\'" | \'"\' ' - 'shortstringitem* \'"\'\n' - ' longstring ::= "\'\'\'" longstringitem* "\'\'\'" | ' - '\'"""\' longstringitem* \'"""\'\n' - ' shortstringitem ::= shortstringchar | stringescapeseq\n' - ' longstringitem ::= longstringchar | stringescapeseq\n' - ' shortstringchar ::= \n' - ' longstringchar ::= \n' - ' stringescapeseq ::= "\\" \n' - '\n' - ' bytesliteral ::= bytesprefix(shortbytes | longbytes)\n' - ' bytesprefix ::= "b" | "B" | "br" | "Br" | "bR" | "BR" | ' - '"rb" | "rB" | "Rb" | "RB"\n' - ' shortbytes ::= "\'" shortbytesitem* "\'" | \'"\' ' - 'shortbytesitem* \'"\'\n' - ' longbytes ::= "\'\'\'" longbytesitem* "\'\'\'" | \'"""\' ' - 'longbytesitem* \'"""\'\n' - ' shortbytesitem ::= shortbyteschar | bytesescapeseq\n' - ' longbytesitem ::= longbyteschar | bytesescapeseq\n' - ' shortbyteschar ::= \n' - ' longbyteschar ::= \n' - ' bytesescapeseq ::= "\\" \n' - '\n' - 'One syntactic restriction not indicated by these productions is ' - 'that\n' - 'whitespace is not allowed between the "stringprefix" or ' - '"bytesprefix"\n' - 'and the rest of the literal. The source character set is defined ' - 'by\n' - 'the encoding declaration; it is UTF-8 if no encoding declaration ' - 'is\n' - 'given in the source file; see section Encoding declarations.\n' - '\n' - 'In plain English: Both types of literals can be enclosed in ' - 'matching\n' - 'single quotes ("\'") or double quotes ("""). They can also be ' - 'enclosed\n' - 'in matching groups of three single or double quotes (these are\n' - 'generally referred to as *triple-quoted strings*). The ' - 'backslash\n' - '("\\") character is used to escape characters that otherwise have ' - 'a\n' - 'special meaning, such as newline, backslash itself, or the quote\n' - 'character.\n' - '\n' - 'Bytes literals are always prefixed with "\'b\'" or "\'B\'"; they ' - 'produce\n' - 'an instance of the "bytes" type instead of the "str" type. They ' - 'may\n' - 'only contain ASCII characters; bytes with a numeric value of 128 ' - 'or\n' - 'greater must be expressed with escapes.\n' - '\n' - 'Both string and bytes literals may optionally be prefixed with a\n' - 'letter "\'r\'" or "\'R\'"; such strings are called *raw strings* ' - 'and treat\n' - 'backslashes as literal characters. As a result, in string ' - 'literals,\n' - '"\'\\U\'" and "\'\\u\'" escapes in raw strings are not treated ' - 'specially.\n' - 'Given that Python 2.x’s raw unicode literals behave differently ' - 'than\n' - 'Python 3.x’s the "\'ur\'" syntax is not supported.\n' - '\n' - 'New in version 3.3: The "\'rb\'" prefix of raw bytes literals has ' - 'been\n' - 'added as a synonym of "\'br\'".\n' - '\n' - 'New in version 3.3: Support for the unicode legacy literal\n' - '("u\'value\'") was reintroduced to simplify the maintenance of ' - 'dual\n' - 'Python 2.x and 3.x codebases. See **PEP 414** for more ' - 'information.\n' - '\n' - 'A string literal with "\'f\'" or "\'F\'" in its prefix is a ' - '*formatted\n' - 'string literal*; see Formatted string literals. The "\'f\'" may ' - 'be\n' - 'combined with "\'r\'", but not with "\'b\'" or "\'u\'", therefore ' - 'raw\n' - 'formatted strings are possible, but formatted bytes literals are ' - 'not.\n' - '\n' - 'In triple-quoted literals, unescaped newlines and quotes are ' - 'allowed\n' - '(and are retained), except that three unescaped quotes in a row\n' - 'terminate the literal. (A “quote” is the character used to open ' - 'the\n' - 'literal, i.e. either "\'" or """.)\n' - '\n' - 'Unless an "\'r\'" or "\'R\'" prefix is present, escape sequences ' - 'in string\n' - 'and bytes literals are interpreted according to rules similar to ' - 'those\n' - 'used by Standard C. The recognized escape sequences are:\n' - '\n' - '+-------------------+-----------------------------------+---------+\n' - '| Escape Sequence | Meaning | Notes ' - '|\n' - '+===================+===================================+=========+\n' - '| "\\newline" | Backslash and newline ignored ' - '| |\n' - '+-------------------+-----------------------------------+---------+\n' - '| "\\\\" | Backslash ("\\") ' - '| |\n' - '+-------------------+-----------------------------------+---------+\n' - '| "\\\'" | Single quote ("\'") ' - '| |\n' - '+-------------------+-----------------------------------+---------+\n' - '| "\\"" | Double quote (""") ' - '| |\n' - '+-------------------+-----------------------------------+---------+\n' - '| "\\a" | ASCII Bell (BEL) ' - '| |\n' - '+-------------------+-----------------------------------+---------+\n' - '| "\\b" | ASCII Backspace (BS) ' - '| |\n' - '+-------------------+-----------------------------------+---------+\n' - '| "\\f" | ASCII Formfeed (FF) ' - '| |\n' - '+-------------------+-----------------------------------+---------+\n' - '| "\\n" | ASCII Linefeed (LF) ' - '| |\n' - '+-------------------+-----------------------------------+---------+\n' - '| "\\r" | ASCII Carriage Return (CR) ' - '| |\n' - '+-------------------+-----------------------------------+---------+\n' - '| "\\t" | ASCII Horizontal Tab (TAB) ' - '| |\n' - '+-------------------+-----------------------------------+---------+\n' - '| "\\v" | ASCII Vertical Tab (VT) ' - '| |\n' - '+-------------------+-----------------------------------+---------+\n' - '| "\\ooo" | Character with octal value *ooo* | ' - '(1,3) |\n' - '+-------------------+-----------------------------------+---------+\n' - '| "\\xhh" | Character with hex value *hh* | ' - '(2,3) |\n' - '+-------------------+-----------------------------------+---------+\n' - '\n' - 'Escape sequences only recognized in string literals are:\n' - '\n' - '+-------------------+-----------------------------------+---------+\n' - '| Escape Sequence | Meaning | Notes ' - '|\n' - '+===================+===================================+=========+\n' - '| "\\N{name}" | Character named *name* in the | ' - '(4) |\n' - '| | Unicode database | ' - '|\n' - '+-------------------+-----------------------------------+---------+\n' - '| "\\uxxxx" | Character with 16-bit hex value | ' - '(5) |\n' - '| | *xxxx* | ' - '|\n' - '+-------------------+-----------------------------------+---------+\n' - '| "\\Uxxxxxxxx" | Character with 32-bit hex value | ' - '(6) |\n' - '| | *xxxxxxxx* | ' - '|\n' - '+-------------------+-----------------------------------+---------+\n' - '\n' - 'Notes:\n' - '\n' - '1. As in Standard C, up to three octal digits are accepted.\n' - '\n' - '2. Unlike in Standard C, exactly two hex digits are required.\n' - '\n' - '3. In a bytes literal, hexadecimal and octal escapes denote the\n' - ' byte with the given value. In a string literal, these escapes\n' - ' denote a Unicode character with the given value.\n' - '\n' - '4. Changed in version 3.3: Support for name aliases [1] has been\n' - ' added.\n' - '\n' - '5. Exactly four hex digits are required.\n' - '\n' - '6. Any Unicode character can be encoded this way. Exactly eight\n' - ' hex digits are required.\n' - '\n' - 'Unlike Standard C, all unrecognized escape sequences are left in ' - 'the\n' - 'string unchanged, i.e., *the backslash is left in the result*. ' - '(This\n' - 'behavior is useful when debugging: if an escape sequence is ' - 'mistyped,\n' - 'the resulting output is more easily recognized as broken.) It is ' - 'also\n' - 'important to note that the escape sequences only recognized in ' - 'string\n' - 'literals fall into the category of unrecognized escapes for ' - 'bytes\n' - 'literals.\n' - '\n' - ' Changed in version 3.6: Unrecognized escape sequences produce ' - 'a\n' - ' DeprecationWarning. In some future version of Python they ' - 'will be\n' - ' a SyntaxError.\n' - '\n' - 'Even in a raw literal, quotes can be escaped with a backslash, ' - 'but the\n' - 'backslash remains in the result; for example, "r"\\""" is a ' - 'valid\n' - 'string literal consisting of two characters: a backslash and a ' - 'double\n' - 'quote; "r"\\"" is not a valid string literal (even a raw string ' - 'cannot\n' - 'end in an odd number of backslashes). Specifically, *a raw ' - 'literal\n' - 'cannot end in a single backslash* (since the backslash would ' - 'escape\n' - 'the following quote character). Note also that a single ' - 'backslash\n' - 'followed by a newline is interpreted as those two characters as ' - 'part\n' - 'of the literal, *not* as a line continuation.\n', - 'subscriptions': 'Subscriptions\n' - '*************\n' + 'A "break" statement executed in the first suite terminates the ' \ + 'loop\n' \ + 'without executing the "else" clause’s suite. A "continue" ' + 'statement\n' \ + 'executed in the first suite skips the rest of the suite and goes ' + 'back\n' \ + 'to testing the expression.\n', + 'with': 'The "with" statement\n' \ + '********************\n' + '\n' + 'The "with" statement is used to wrap the execution of a block with\n' + 'methods defined by a context manager (see section With Statement\n' + 'Context Managers). This allows common "try"…"except"…"finally" ' \ + 'usage\n' + 'patterns to be encapsulated for convenient reuse.\n' + '\n' + ' with_stmt ::= "with" ( "(" with_stmt_contents ","? ")" | ' \ + 'with_stmt_contents ) ":" suite\n' + ' with_stmt_contents ::= with_item ("," with_item)*\n' + ' with_item ::= expression ["as" target]\n' + '\n' + 'The execution of the "with" statement with one “item” proceeds as\n' + 'follows:\n' + '\n' + '1. The context expression (the expression given in the "with_item") ' + 'is\n' + ' evaluated to obtain a context manager.\n' + '\n' + '2. The context manager’s "__enter__()" is loaded for later use.\n' '\n' - 'A subscription selects an item of a sequence (string, tuple ' - 'or list)\n' - 'or mapping (dictionary) object:\n' + '3. The context manager’s "__exit__()" is loaded for later use.\n' '\n' - ' subscription ::= primary "[" expression_list "]"\n' + '4. The context manager’s "__enter__()" method is invoked.\n' \ '\n' - 'The primary must evaluate to an object that supports ' - 'subscription\n' - '(lists or dictionaries for example). User-defined objects ' - 'can support\n' - 'subscription by defining a "__getitem__()" method.\n' + '5. If a target was included in the "with" statement, the return ' + 'value\n' + ' from "__enter__()" is assigned to it.\n' + '\n' + ' Note:\n' + '\n' + ' The "with" statement guarantees that if the "__enter__()" ' + 'method\n' + ' returns without an error, then "__exit__()" will always be\n' + ' called. Thus, if an error occurs during the assignment to the\n' + ' target list, it will be treated the same as an error occurring\n' + ' within the suite would be. See step 7 below.\n' + '\n' + '6. The suite is executed.\n' \ '\n' - 'For built-in objects, there are two types of objects that ' - 'support\n' - 'subscription:\n' + '7. The context manager’s "__exit__()" method is invoked. If an\n' + ' exception caused the suite to be exited, its type, value, and\n' + ' traceback are passed as arguments to "__exit__()". Otherwise, ' + 'three\n' \ + ' "None" arguments are supplied.\n' '\n' - 'If the primary is a mapping, the expression list must ' - 'evaluate to an\n' - 'object whose value is one of the keys of the mapping, and ' + ' If the suite was exited due to an exception, and the return ' + 'value\n' + ' from the "__exit__()" method was false, the exception is ' + 'reraised.\n' + ' If the return value was true, the exception is suppressed, and\n' + ' execution continues with the statement following the "with"\n' + ' statement.\n' + '\n' + ' If the suite was exited for any reason other than an exception, ' 'the\n' - 'subscription selects the value in the mapping that ' - 'corresponds to that\n' - 'key. (The expression list is a tuple except if it has ' - 'exactly one\n' - 'item.)\n' + ' return value from "__exit__()" is ignored, and execution ' + 'proceeds\n' + ' at the normal location for the kind of exit that was taken.\n' '\n' - 'If the primary is a sequence, the expression list must ' - 'evaluate to an\n' - 'integer or a slice (as discussed in the following ' - 'section).\n' + 'The following code:\n' '\n' - 'The formal syntax makes no special provision for negative ' - 'indices in\n' - 'sequences; however, built-in sequences all provide a ' - '"__getitem__()"\n' - 'method that interprets negative indices by adding the ' - 'length of the\n' - 'sequence to the index (so that "x[-1]" selects the last ' - 'item of "x").\n' - 'The resulting value must be a nonnegative integer less than ' - 'the number\n' - 'of items in the sequence, and the subscription selects the ' - 'item whose\n' - 'index is that value (counting from zero). Since the support ' - 'for\n' - 'negative indices and slicing occurs in the object’s ' - '"__getitem__()"\n' - 'method, subclasses overriding this method will need to ' - 'explicitly add\n' - 'that support.\n' + ' with EXPRESSION as TARGET:\n' + ' SUITE\n' '\n' - 'A string’s items are characters. A character is not a ' - 'separate data\n' - 'type but a string of exactly one character.\n', - 'truth': 'Truth Value Testing\n' - '*******************\n' - '\n' - 'Any object can be tested for truth value, for use in an "if" or\n' - '"while" condition or as operand of the Boolean operations below.\n' - '\n' - 'By default, an object is considered true unless its class defines\n' - 'either a "__bool__()" method that returns "False" or a "__len__()"\n' - 'method that returns zero, when called with the object. [1] Here ' - 'are\n' - 'most of the built-in objects considered false:\n' - '\n' - '* constants defined to be false: "None" and "False".\n' - '\n' - '* zero of any numeric type: "0", "0.0", "0j", "Decimal(0)",\n' - ' "Fraction(0, 1)"\n' - '\n' - '* empty sequences and collections: "\'\'", "()", "[]", "{}", ' - '"set()",\n' - ' "range(0)"\n' - '\n' - 'Operations and built-in functions that have a Boolean result ' - 'always\n' - 'return "0" or "False" for false and "1" or "True" for true, unless\n' - 'otherwise stated. (Important exception: the Boolean operations ' - '"or"\n' - 'and "and" always return one of their operands.)\n', - 'try': 'The "try" statement\n' - '*******************\n' - '\n' - 'The "try" statement specifies exception handlers and/or cleanup code\n' - 'for a group of statements:\n' - '\n' - ' try_stmt ::= try1_stmt | try2_stmt\n' - ' try1_stmt ::= "try" ":" suite\n' - ' ("except" [expression ["as" identifier]] ":" ' - 'suite)+\n' - ' ["else" ":" suite]\n' - ' ["finally" ":" suite]\n' - ' try2_stmt ::= "try" ":" suite\n' - ' "finally" ":" suite\n' - '\n' - 'The "except" clause(s) specify one or more exception handlers. When ' - 'no\n' - 'exception occurs in the "try" clause, no exception handler is\n' - 'executed. When an exception occurs in the "try" suite, a search for ' - 'an\n' - 'exception handler is started. This search inspects the except ' - 'clauses\n' - 'in turn until one is found that matches the exception. An ' - 'expression-\n' - 'less except clause, if present, must be last; it matches any\n' - 'exception. For an except clause with an expression, that expression\n' - 'is evaluated, and the clause matches the exception if the resulting\n' - 'object is “compatible” with the exception. An object is compatible\n' - 'with an exception if it is the class or a base class of the ' - 'exception\n' - 'object or a tuple containing an item compatible with the exception.\n' - '\n' - 'If no except clause matches the exception, the search for an ' - 'exception\n' - 'handler continues in the surrounding code and on the invocation ' - 'stack.\n' - '[1]\n' - '\n' - 'If the evaluation of an expression in the header of an except clause\n' - 'raises an exception, the original search for a handler is canceled ' - 'and\n' - 'a search starts for the new exception in the surrounding code and on\n' - 'the call stack (it is treated as if the entire "try" statement ' - 'raised\n' - 'the exception).\n' - '\n' - 'When a matching except clause is found, the exception is assigned to\n' - 'the target specified after the "as" keyword in that except clause, ' - 'if\n' - 'present, and the except clause’s suite is executed. All except\n' - 'clauses must have an executable block. When the end of this block ' - 'is\n' - 'reached, execution continues normally after the entire try ' - 'statement.\n' - '(This means that if two nested handlers exist for the same ' - 'exception,\n' - 'and the exception occurs in the try clause of the inner handler, the\n' - 'outer handler will not handle the exception.)\n' - '\n' - 'When an exception has been assigned using "as target", it is cleared\n' - 'at the end of the except clause. This is as if\n' - '\n' - ' except E as N:\n' - ' foo\n' - '\n' - 'was translated to\n' - '\n' - ' except E as N:\n' - ' try:\n' - ' foo\n' - ' finally:\n' - ' del N\n' - '\n' - 'This means the exception must be assigned to a different name to be\n' - 'able to refer to it after the except clause. Exceptions are cleared\n' - 'because with the traceback attached to them, they form a reference\n' - 'cycle with the stack frame, keeping all locals in that frame alive\n' - 'until the next garbage collection occurs.\n' - '\n' - 'Before an except clause’s suite is executed, details about the\n' - 'exception are stored in the "sys" module and can be accessed via\n' - '"sys.exc_info()". "sys.exc_info()" returns a 3-tuple consisting of ' - 'the\n' - 'exception class, the exception instance and a traceback object (see\n' - 'section The standard type hierarchy) identifying the point in the\n' - 'program where the exception occurred. "sys.exc_info()" values are\n' - 'restored to their previous values (before the call) when returning\n' - 'from a function that handled an exception.\n' - '\n' - 'The optional "else" clause is executed if the control flow leaves ' - 'the\n' - '"try" suite, no exception was raised, and no "return", "continue", ' - 'or\n' - '"break" statement was executed. Exceptions in the "else" clause are\n' - 'not handled by the preceding "except" clauses.\n' - '\n' - 'If "finally" is present, it specifies a ‘cleanup’ handler. The ' - '"try"\n' - 'clause is executed, including any "except" and "else" clauses. If ' - 'an\n' - 'exception occurs in any of the clauses and is not handled, the\n' - 'exception is temporarily saved. The "finally" clause is executed. ' - 'If\n' - 'there is a saved exception it is re-raised at the end of the ' - '"finally"\n' - 'clause. If the "finally" clause raises another exception, the saved\n' - 'exception is set as the context of the new exception. If the ' - '"finally"\n' - 'clause executes a "return" or "break" statement, the saved exception\n' - 'is discarded:\n' - '\n' - ' >>> def f():\n' - ' ... try:\n' - ' ... 1/0\n' - ' ... finally:\n' - ' ... return 42\n' - ' ...\n' - ' >>> f()\n' - ' 42\n' - '\n' - 'The exception information is not available to the program during\n' - 'execution of the "finally" clause.\n' - '\n' - 'When a "return", "break" or "continue" statement is executed in the\n' - '"try" suite of a "try"…"finally" statement, the "finally" clause is\n' - 'also executed ‘on the way out.’ A "continue" statement is illegal in\n' - 'the "finally" clause. (The reason is a problem with the current\n' - 'implementation — this restriction may be lifted in the future).\n' - '\n' - 'The return value of a function is determined by the last "return"\n' - 'statement executed. Since the "finally" clause always executes, a\n' - '"return" statement executed in the "finally" clause will always be ' - 'the\n' - 'last one executed:\n' - '\n' - ' >>> def foo():\n' - ' ... try:\n' - " ... return 'try'\n" - ' ... finally:\n' - " ... return 'finally'\n" - ' ...\n' - ' >>> foo()\n' - " 'finally'\n" - '\n' - 'Additional information on exceptions can be found in section\n' - 'Exceptions, and information on using the "raise" statement to ' - 'generate\n' - 'exceptions may be found in section The raise statement.\n', - 'types': 'The standard type hierarchy\n' - '***************************\n' - '\n' - 'Below is a list of the types that are built into Python. ' - 'Extension\n' - 'modules (written in C, Java, or other languages, depending on the\n' - 'implementation) can define additional types. Future versions of\n' - 'Python may add types to the type hierarchy (e.g., rational ' - 'numbers,\n' - 'efficiently stored arrays of integers, etc.), although such ' - 'additions\n' - 'will often be provided via the standard library instead.\n' - '\n' - 'Some of the type descriptions below contain a paragraph listing\n' - '‘special attributes.’ These are attributes that provide access to ' - 'the\n' - 'implementation and are not intended for general use. Their ' - 'definition\n' - 'may change in the future.\n' - '\n' - 'None\n' - ' This type has a single value. There is a single object with ' - 'this\n' - ' value. This object is accessed through the built-in name "None". ' - 'It\n' - ' is used to signify the absence of a value in many situations, ' - 'e.g.,\n' - ' it is returned from functions that don’t explicitly return\n' - ' anything. Its truth value is false.\n' - '\n' - 'NotImplemented\n' - ' This type has a single value. There is a single object with ' - 'this\n' - ' value. This object is accessed through the built-in name\n' - ' "NotImplemented". Numeric methods and rich comparison methods\n' - ' should return this value if they do not implement the operation ' - 'for\n' - ' the operands provided. (The interpreter will then try the\n' - ' reflected operation, or some other fallback, depending on the\n' - ' operator.) Its truth value is true.\n' - '\n' - ' See Implementing the arithmetic operations for more details.\n' - '\n' - 'Ellipsis\n' - ' This type has a single value. There is a single object with ' - 'this\n' - ' value. This object is accessed through the literal "..." or the\n' - ' built-in name "Ellipsis". Its truth value is true.\n' - '\n' - '"numbers.Number"\n' - ' These are created by numeric literals and returned as results ' - 'by\n' - ' arithmetic operators and arithmetic built-in functions. ' - 'Numeric\n' - ' objects are immutable; once created their value never changes.\n' - ' Python numbers are of course strongly related to mathematical\n' - ' numbers, but subject to the limitations of numerical ' - 'representation\n' - ' in computers.\n' - '\n' - ' Python distinguishes between integers, floating point numbers, ' - 'and\n' - ' complex numbers:\n' - '\n' - ' "numbers.Integral"\n' - ' These represent elements from the mathematical set of ' - 'integers\n' - ' (positive and negative).\n' - '\n' - ' There are two types of integers:\n' - '\n' - ' Integers ("int")\n' - '\n' - ' These represent numbers in an unlimited range, subject to\n' - ' available (virtual) memory only. For the purpose of ' - 'shift\n' - ' and mask operations, a binary representation is assumed, ' - 'and\n' - ' negative numbers are represented in a variant of 2’s\n' - ' complement which gives the illusion of an infinite string ' - 'of\n' - ' sign bits extending to the left.\n' - '\n' - ' Booleans ("bool")\n' - ' These represent the truth values False and True. The two\n' - ' objects representing the values "False" and "True" are ' - 'the\n' - ' only Boolean objects. The Boolean type is a subtype of ' - 'the\n' - ' integer type, and Boolean values behave like the values 0 ' - 'and\n' - ' 1, respectively, in almost all contexts, the exception ' - 'being\n' - ' that when converted to a string, the strings ""False"" or\n' - ' ""True"" are returned, respectively.\n' - '\n' - ' The rules for integer representation are intended to give ' - 'the\n' - ' most meaningful interpretation of shift and mask operations\n' - ' involving negative integers.\n' - '\n' - ' "numbers.Real" ("float")\n' - ' These represent machine-level double precision floating ' - 'point\n' - ' numbers. You are at the mercy of the underlying machine\n' - ' architecture (and C or Java implementation) for the accepted\n' - ' range and handling of overflow. Python does not support ' - 'single-\n' - ' precision floating point numbers; the savings in processor ' - 'and\n' - ' memory usage that are usually the reason for using these are\n' - ' dwarfed by the overhead of using objects in Python, so there ' - 'is\n' - ' no reason to complicate the language with two kinds of ' - 'floating\n' - ' point numbers.\n' - '\n' - ' "numbers.Complex" ("complex")\n' - ' These represent complex numbers as a pair of machine-level\n' - ' double precision floating point numbers. The same caveats ' - 'apply\n' - ' as for floating point numbers. The real and imaginary parts ' - 'of a\n' - ' complex number "z" can be retrieved through the read-only\n' - ' attributes "z.real" and "z.imag".\n' - '\n' - 'Sequences\n' - ' These represent finite ordered sets indexed by non-negative\n' - ' numbers. The built-in function "len()" returns the number of ' - 'items\n' - ' of a sequence. When the length of a sequence is *n*, the index ' - 'set\n' - ' contains the numbers 0, 1, …, *n*-1. Item *i* of sequence *a* ' - 'is\n' - ' selected by "a[i]".\n' - '\n' - ' Sequences also support slicing: "a[i:j]" selects all items with\n' - ' index *k* such that *i* "<=" *k* "<" *j*. When used as an\n' - ' expression, a slice is a sequence of the same type. This ' - 'implies\n' - ' that the index set is renumbered so that it starts at 0.\n' - '\n' - ' Some sequences also support “extended slicing” with a third ' - '“step”\n' - ' parameter: "a[i:j:k]" selects all items of *a* with index *x* ' - 'where\n' - ' "x = i + n*k", *n* ">=" "0" and *i* "<=" *x* "<" *j*.\n' - '\n' - ' Sequences are distinguished according to their mutability:\n' - '\n' - ' Immutable sequences\n' - ' An object of an immutable sequence type cannot change once it ' - 'is\n' - ' created. (If the object contains references to other ' - 'objects,\n' - ' these other objects may be mutable and may be changed; ' - 'however,\n' - ' the collection of objects directly referenced by an ' - 'immutable\n' - ' object cannot change.)\n' - '\n' - ' The following types are immutable sequences:\n' - '\n' - ' Strings\n' - ' A string is a sequence of values that represent Unicode ' - 'code\n' - ' points. All the code points in the range "U+0000 - ' - 'U+10FFFF"\n' - ' can be represented in a string. Python doesn’t have a ' - '"char"\n' - ' type; instead, every code point in the string is ' - 'represented\n' - ' as a string object with length "1". The built-in ' - 'function\n' - ' "ord()" converts a code point from its string form to an\n' - ' integer in the range "0 - 10FFFF"; "chr()" converts an\n' - ' integer in the range "0 - 10FFFF" to the corresponding ' - 'length\n' - ' "1" string object. "str.encode()" can be used to convert ' - 'a\n' - ' "str" to "bytes" using the given text encoding, and\n' - ' "bytes.decode()" can be used to achieve the opposite.\n' - '\n' - ' Tuples\n' - ' The items of a tuple are arbitrary Python objects. Tuples ' - 'of\n' - ' two or more items are formed by comma-separated lists of\n' - ' expressions. A tuple of one item (a ‘singleton’) can be\n' - ' formed by affixing a comma to an expression (an expression ' - 'by\n' - ' itself does not create a tuple, since parentheses must be\n' - ' usable for grouping of expressions). An empty tuple can ' - 'be\n' - ' formed by an empty pair of parentheses.\n' - '\n' - ' Bytes\n' - ' A bytes object is an immutable array. The items are ' - '8-bit\n' - ' bytes, represented by integers in the range 0 <= x < 256.\n' - ' Bytes literals (like "b\'abc\'") and the built-in ' - '"bytes()"\n' - ' constructor can be used to create bytes objects. Also, ' - 'bytes\n' - ' objects can be decoded to strings via the "decode()" ' - 'method.\n' - '\n' - ' Mutable sequences\n' - ' Mutable sequences can be changed after they are created. ' - 'The\n' - ' subscription and slicing notations can be used as the target ' - 'of\n' - ' assignment and "del" (delete) statements.\n' - '\n' - ' There are currently two intrinsic mutable sequence types:\n' - '\n' - ' Lists\n' - ' The items of a list are arbitrary Python objects. Lists ' - 'are\n' - ' formed by placing a comma-separated list of expressions ' - 'in\n' - ' square brackets. (Note that there are no special cases ' - 'needed\n' - ' to form lists of length 0 or 1.)\n' - '\n' - ' Byte Arrays\n' - ' A bytearray object is a mutable array. They are created ' - 'by\n' - ' the built-in "bytearray()" constructor. Aside from being\n' - ' mutable (and hence unhashable), byte arrays otherwise ' - 'provide\n' - ' the same interface and functionality as immutable "bytes"\n' - ' objects.\n' - '\n' - ' The extension module "array" provides an additional example ' - 'of a\n' - ' mutable sequence type, as does the "collections" module.\n' - '\n' - 'Set types\n' - ' These represent unordered, finite sets of unique, immutable\n' - ' objects. As such, they cannot be indexed by any subscript. ' - 'However,\n' - ' they can be iterated over, and the built-in function "len()"\n' - ' returns the number of items in a set. Common uses for sets are ' - 'fast\n' - ' membership testing, removing duplicates from a sequence, and\n' - ' computing mathematical operations such as intersection, union,\n' - ' difference, and symmetric difference.\n' - '\n' - ' For set elements, the same immutability rules apply as for\n' - ' dictionary keys. Note that numeric types obey the normal rules ' - 'for\n' - ' numeric comparison: if two numbers compare equal (e.g., "1" and\n' - ' "1.0"), only one of them can be contained in a set.\n' - '\n' - ' There are currently two intrinsic set types:\n' - '\n' - ' Sets\n' - ' These represent a mutable set. They are created by the ' - 'built-in\n' - ' "set()" constructor and can be modified afterwards by ' - 'several\n' - ' methods, such as "add()".\n' - '\n' - ' Frozen sets\n' - ' These represent an immutable set. They are created by the\n' - ' built-in "frozenset()" constructor. As a frozenset is ' - 'immutable\n' - ' and *hashable*, it can be used again as an element of ' - 'another\n' - ' set, or as a dictionary key.\n' - '\n' - 'Mappings\n' - ' These represent finite sets of objects indexed by arbitrary ' - 'index\n' - ' sets. The subscript notation "a[k]" selects the item indexed by ' - '"k"\n' - ' from the mapping "a"; this can be used in expressions and as ' - 'the\n' - ' target of assignments or "del" statements. The built-in ' - 'function\n' - ' "len()" returns the number of items in a mapping.\n' - '\n' - ' There is currently a single intrinsic mapping type:\n' - '\n' - ' Dictionaries\n' - ' These represent finite sets of objects indexed by nearly\n' - ' arbitrary values. The only types of values not acceptable ' - 'as\n' - ' keys are values containing lists or dictionaries or other\n' - ' mutable types that are compared by value rather than by ' - 'object\n' - ' identity, the reason being that the efficient implementation ' - 'of\n' - ' dictionaries requires a key’s hash value to remain constant.\n' - ' Numeric types used for keys obey the normal rules for ' - 'numeric\n' - ' comparison: if two numbers compare equal (e.g., "1" and ' - '"1.0")\n' - ' then they can be used interchangeably to index the same\n' - ' dictionary entry.\n' - '\n' - ' Dictionaries are mutable; they can be created by the "{...}"\n' - ' notation (see section Dictionary displays).\n' - '\n' - ' The extension modules "dbm.ndbm" and "dbm.gnu" provide\n' - ' additional examples of mapping types, as does the ' - '"collections"\n' - ' module.\n' - '\n' - 'Callable types\n' - ' These are the types to which the function call operation (see\n' - ' section Calls) can be applied:\n' - '\n' - ' User-defined functions\n' - ' A user-defined function object is created by a function\n' - ' definition (see section Function definitions). It should be\n' - ' called with an argument list containing the same number of ' - 'items\n' - ' as the function’s formal parameter list.\n' - '\n' - ' Special attributes:\n' - '\n' - ' ' - '+---------------------------+---------------------------------+-------------+\n' - ' | Attribute | Meaning ' - '| |\n' - ' ' - '+===========================+=================================+=============+\n' - ' | "__doc__" | The function’s documentation ' - '| Writable |\n' - ' | | string, or "None" if ' - '| |\n' - ' | | unavailable; not inherited by ' - '| |\n' - ' | | subclasses ' - '| |\n' - ' ' - '+---------------------------+---------------------------------+-------------+\n' - ' | "__name__" | The function’s name ' - '| Writable |\n' - ' ' - '+---------------------------+---------------------------------+-------------+\n' - ' | "__qualname__" | The function’s *qualified name* ' - '| Writable |\n' - ' | | New in version 3.3. ' - '| |\n' - ' ' - '+---------------------------+---------------------------------+-------------+\n' - ' | "__module__" | The name of the module the ' - '| Writable |\n' - ' | | function was defined in, or ' - '| |\n' - ' | | "None" if unavailable. ' - '| |\n' - ' ' - '+---------------------------+---------------------------------+-------------+\n' - ' | "__defaults__" | A tuple containing default ' - '| Writable |\n' - ' | | argument values for those ' - '| |\n' - ' | | arguments that have defaults, ' - '| |\n' - ' | | or "None" if no arguments have ' - '| |\n' - ' | | a default value ' - '| |\n' - ' ' - '+---------------------------+---------------------------------+-------------+\n' - ' | "__code__" | The code object representing ' - '| Writable |\n' - ' | | the compiled function body. ' - '| |\n' - ' ' - '+---------------------------+---------------------------------+-------------+\n' - ' | "__globals__" | A reference to the dictionary ' - '| Read-only |\n' - ' | | that holds the function’s ' - '| |\n' - ' | | global variables — the global ' - '| |\n' - ' | | namespace of the module in ' - '| |\n' - ' | | which the function was defined. ' - '| |\n' - ' ' - '+---------------------------+---------------------------------+-------------+\n' - ' | "__dict__" | The namespace supporting ' - '| Writable |\n' - ' | | arbitrary function attributes. ' - '| |\n' - ' ' - '+---------------------------+---------------------------------+-------------+\n' - ' | "__closure__" | "None" or a tuple of cells that ' - '| Read-only |\n' - ' | | contain bindings for the ' - '| |\n' - ' | | function’s free variables. ' - '| |\n' - ' ' - '+---------------------------+---------------------------------+-------------+\n' - ' | "__annotations__" | A dict containing annotations ' - '| Writable |\n' - ' | | of parameters. The keys of the ' - '| |\n' - ' | | dict are the parameter names, ' - '| |\n' - ' | | and "\'return\'" for the ' - 'return | |\n' - ' | | annotation, if provided. ' - '| |\n' - ' ' - '+---------------------------+---------------------------------+-------------+\n' - ' | "__kwdefaults__" | A dict containing defaults for ' - '| Writable |\n' - ' | | keyword-only parameters. ' - '| |\n' - ' ' - '+---------------------------+---------------------------------+-------------+\n' - '\n' - ' Most of the attributes labelled “Writable” check the type of ' - 'the\n' - ' assigned value.\n' - '\n' - ' Function objects also support getting and setting arbitrary\n' - ' attributes, which can be used, for example, to attach ' - 'metadata\n' - ' to functions. Regular attribute dot-notation is used to get ' - 'and\n' - ' set such attributes. *Note that the current implementation ' - 'only\n' - ' supports function attributes on user-defined functions. ' - 'Function\n' - ' attributes on built-in functions may be supported in the\n' - ' future.*\n' - '\n' - ' Additional information about a function’s definition can be\n' - ' retrieved from its code object; see the description of ' - 'internal\n' - ' types below.\n' - '\n' - ' Instance methods\n' - ' An instance method object combines a class, a class instance ' - 'and\n' - ' any callable object (normally a user-defined function).\n' - '\n' - ' Special read-only attributes: "__self__" is the class ' - 'instance\n' - ' object, "__func__" is the function object; "__doc__" is the\n' - ' method’s documentation (same as "__func__.__doc__"); ' - '"__name__"\n' - ' is the method name (same as "__func__.__name__"); ' - '"__module__"\n' - ' is the name of the module the method was defined in, or ' - '"None"\n' - ' if unavailable.\n' - '\n' - ' Methods also support accessing (but not setting) the ' - 'arbitrary\n' - ' function attributes on the underlying function object.\n' - '\n' - ' User-defined method objects may be created when getting an\n' - ' attribute of a class (perhaps via an instance of that class), ' - 'if\n' - ' that attribute is a user-defined function object or a class\n' - ' method object.\n' - '\n' - ' When an instance method object is created by retrieving a ' - 'user-\n' - ' defined function object from a class via one of its ' - 'instances,\n' - ' its "__self__" attribute is the instance, and the method ' - 'object\n' - ' is said to be bound. The new method’s "__func__" attribute ' - 'is\n' - ' the original function object.\n' - '\n' - ' When a user-defined method object is created by retrieving\n' - ' another method object from a class or instance, the behaviour ' - 'is\n' - ' the same as for a function object, except that the ' - '"__func__"\n' - ' attribute of the new instance is not the original method ' - 'object\n' - ' but its "__func__" attribute.\n' - '\n' - ' When an instance method object is created by retrieving a ' - 'class\n' - ' method object from a class or instance, its "__self__" ' - 'attribute\n' - ' is the class itself, and its "__func__" attribute is the\n' - ' function object underlying the class method.\n' - '\n' - ' When an instance method object is called, the underlying\n' - ' function ("__func__") is called, inserting the class ' - 'instance\n' - ' ("__self__") in front of the argument list. For instance, ' - 'when\n' - ' "C" is a class which contains a definition for a function ' - '"f()",\n' - ' and "x" is an instance of "C", calling "x.f(1)" is equivalent ' - 'to\n' - ' calling "C.f(x, 1)".\n' - '\n' - ' When an instance method object is derived from a class ' - 'method\n' - ' object, the “class instance” stored in "__self__" will ' - 'actually\n' - ' be the class itself, so that calling either "x.f(1)" or ' - '"C.f(1)"\n' - ' is equivalent to calling "f(C,1)" where "f" is the ' - 'underlying\n' - ' function.\n' - '\n' - ' Note that the transformation from function object to ' - 'instance\n' - ' method object happens each time the attribute is retrieved ' - 'from\n' - ' the instance. In some cases, a fruitful optimization is to\n' - ' assign the attribute to a local variable and call that local\n' - ' variable. Also notice that this transformation only happens ' - 'for\n' - ' user-defined functions; other callable objects (and all non-\n' - ' callable objects) are retrieved without transformation. It ' - 'is\n' - ' also important to note that user-defined functions which are\n' - ' attributes of a class instance are not converted to bound\n' - ' methods; this *only* happens when the function is an ' - 'attribute\n' - ' of the class.\n' - '\n' - ' Generator functions\n' - ' A function or method which uses the "yield" statement (see\n' - ' section The yield statement) is called a *generator ' - 'function*.\n' - ' Such a function, when called, always returns an iterator ' - 'object\n' - ' which can be used to execute the body of the function: ' - 'calling\n' - ' the iterator’s "iterator.__next__()" method will cause the\n' - ' function to execute until it provides a value using the ' - '"yield"\n' - ' statement. When the function executes a "return" statement ' - 'or\n' - ' falls off the end, a "StopIteration" exception is raised and ' - 'the\n' - ' iterator will have reached the end of the set of values to ' - 'be\n' - ' returned.\n' - '\n' - ' Coroutine functions\n' - ' A function or method which is defined using "async def" is\n' - ' called a *coroutine function*. Such a function, when ' - 'called,\n' - ' returns a *coroutine* object. It may contain "await"\n' - ' expressions, as well as "async with" and "async for" ' - 'statements.\n' - ' See also the Coroutine Objects section.\n' - '\n' - ' Asynchronous generator functions\n' - ' A function or method which is defined using "async def" and\n' - ' which uses the "yield" statement is called a *asynchronous\n' - ' generator function*. Such a function, when called, returns ' - 'an\n' - ' asynchronous iterator object which can be used in an "async ' - 'for"\n' - ' statement to execute the body of the function.\n' - '\n' - ' Calling the asynchronous iterator’s "aiterator.__anext__()"\n' - ' method will return an *awaitable* which when awaited will\n' - ' execute until it provides a value using the "yield" ' - 'expression.\n' - ' When the function executes an empty "return" statement or ' - 'falls\n' - ' off the end, a "StopAsyncIteration" exception is raised and ' - 'the\n' - ' asynchronous iterator will have reached the end of the set ' - 'of\n' - ' values to be yielded.\n' - '\n' - ' Built-in functions\n' - ' A built-in function object is a wrapper around a C function.\n' - ' Examples of built-in functions are "len()" and "math.sin()"\n' - ' ("math" is a standard built-in module). The number and type ' - 'of\n' - ' the arguments are determined by the C function. Special ' - 'read-\n' - ' only attributes: "__doc__" is the function’s documentation\n' - ' string, or "None" if unavailable; "__name__" is the ' - 'function’s\n' - ' name; "__self__" is set to "None" (but see the next item);\n' - ' "__module__" is the name of the module the function was ' - 'defined\n' - ' in or "None" if unavailable.\n' - '\n' - ' Built-in methods\n' - ' This is really a different disguise of a built-in function, ' - 'this\n' - ' time containing an object passed to the C function as an\n' - ' implicit extra argument. An example of a built-in method is\n' - ' "alist.append()", assuming *alist* is a list object. In this\n' - ' case, the special read-only attribute "__self__" is set to ' - 'the\n' - ' object denoted by *alist*.\n' - '\n' - ' Classes\n' - ' Classes are callable. These objects normally act as ' - 'factories\n' - ' for new instances of themselves, but variations are possible ' - 'for\n' - ' class types that override "__new__()". The arguments of the\n' - ' call are passed to "__new__()" and, in the typical case, to\n' - ' "__init__()" to initialize the new instance.\n' - '\n' - ' Class Instances\n' - ' Instances of arbitrary classes can be made callable by ' - 'defining\n' - ' a "__call__()" method in their class.\n' - '\n' - 'Modules\n' - ' Modules are a basic organizational unit of Python code, and are\n' - ' created by the import system as invoked either by the "import"\n' - ' statement (see "import"), or by calling functions such as\n' - ' "importlib.import_module()" and built-in "__import__()". A ' - 'module\n' - ' object has a namespace implemented by a dictionary object (this ' - 'is\n' - ' the dictionary referenced by the "__globals__" attribute of\n' - ' functions defined in the module). Attribute references are\n' - ' translated to lookups in this dictionary, e.g., "m.x" is ' - 'equivalent\n' - ' to "m.__dict__["x"]". A module object does not contain the code\n' - ' object used to initialize the module (since it isn’t needed ' - 'once\n' - ' the initialization is done).\n' - '\n' - ' Attribute assignment updates the module’s namespace dictionary,\n' - ' e.g., "m.x = 1" is equivalent to "m.__dict__["x"] = 1".\n' - '\n' - ' Predefined (writable) attributes: "__name__" is the module’s ' - 'name;\n' - ' "__doc__" is the module’s documentation string, or "None" if\n' - ' unavailable; "__annotations__" (optional) is a dictionary\n' - ' containing *variable annotations* collected during module body\n' - ' execution; "__file__" is the pathname of the file from which ' - 'the\n' - ' module was loaded, if it was loaded from a file. The "__file__"\n' - ' attribute may be missing for certain types of modules, such as ' - 'C\n' - ' modules that are statically linked into the interpreter; for\n' - ' extension modules loaded dynamically from a shared library, it ' - 'is\n' - ' the pathname of the shared library file.\n' - '\n' - ' Special read-only attribute: "__dict__" is the module’s ' - 'namespace\n' - ' as a dictionary object.\n' - '\n' - ' **CPython implementation detail:** Because of the way CPython\n' - ' clears module dictionaries, the module dictionary will be ' - 'cleared\n' - ' when the module falls out of scope even if the dictionary still ' - 'has\n' - ' live references. To avoid this, copy the dictionary or keep ' - 'the\n' - ' module around while using its dictionary directly.\n' - '\n' - 'Custom classes\n' - ' Custom class types are typically created by class definitions ' - '(see\n' - ' section Class definitions). A class has a namespace implemented ' - 'by\n' - ' a dictionary object. Class attribute references are translated ' - 'to\n' - ' lookups in this dictionary, e.g., "C.x" is translated to\n' - ' "C.__dict__["x"]" (although there are a number of hooks which ' - 'allow\n' - ' for other means of locating attributes). When the attribute name ' - 'is\n' - ' not found there, the attribute search continues in the base\n' - ' classes. This search of the base classes uses the C3 method\n' - ' resolution order which behaves correctly even in the presence ' - 'of\n' - ' ‘diamond’ inheritance structures where there are multiple\n' - ' inheritance paths leading back to a common ancestor. Additional\n' - ' details on the C3 MRO used by Python can be found in the\n' - ' documentation accompanying the 2.3 release at\n' - ' https://www.python.org/download/releases/2.3/mro/.\n' - '\n' - ' When a class attribute reference (for class "C", say) would ' - 'yield a\n' - ' class method object, it is transformed into an instance method\n' - ' object whose "__self__" attribute is "C". When it would yield ' - 'a\n' - ' static method object, it is transformed into the object wrapped ' - 'by\n' - ' the static method object. See section Implementing Descriptors ' - 'for\n' - ' another way in which attributes retrieved from a class may ' - 'differ\n' - ' from those actually contained in its "__dict__".\n' - '\n' - ' Class attribute assignments update the class’s dictionary, ' - 'never\n' - ' the dictionary of a base class.\n' - '\n' - ' A class object can be called (see above) to yield a class ' - 'instance\n' - ' (see below).\n' - '\n' - ' Special attributes: "__name__" is the class name; "__module__" ' - 'is\n' - ' the module name in which the class was defined; "__dict__" is ' - 'the\n' - ' dictionary containing the class’s namespace; "__bases__" is a ' - 'tuple\n' - ' containing the base classes, in the order of their occurrence ' - 'in\n' - ' the base class list; "__doc__" is the class’s documentation ' - 'string,\n' - ' or "None" if undefined; "__annotations__" (optional) is a\n' - ' dictionary containing *variable annotations* collected during ' - 'class\n' - ' body execution.\n' - '\n' - 'Class instances\n' - ' A class instance is created by calling a class object (see ' - 'above).\n' - ' A class instance has a namespace implemented as a dictionary ' - 'which\n' - ' is the first place in which attribute references are searched.\n' - ' When an attribute is not found there, and the instance’s class ' - 'has\n' - ' an attribute by that name, the search continues with the class\n' - ' attributes. If a class attribute is found that is a ' - 'user-defined\n' - ' function object, it is transformed into an instance method ' - 'object\n' - ' whose "__self__" attribute is the instance. Static method and\n' - ' class method objects are also transformed; see above under\n' - ' “Classes”. See section Implementing Descriptors for another way ' - 'in\n' - ' which attributes of a class retrieved via its instances may ' - 'differ\n' - ' from the objects actually stored in the class’s "__dict__". If ' - 'no\n' - ' class attribute is found, and the object’s class has a\n' - ' "__getattr__()" method, that is called to satisfy the lookup.\n' - '\n' - ' Attribute assignments and deletions update the instance’s\n' - ' dictionary, never a class’s dictionary. If the class has a\n' - ' "__setattr__()" or "__delattr__()" method, this is called ' - 'instead\n' - ' of updating the instance dictionary directly.\n' - '\n' - ' Class instances can pretend to be numbers, sequences, or ' - 'mappings\n' - ' if they have methods with certain special names. See section\n' - ' Special method names.\n' - '\n' - ' Special attributes: "__dict__" is the attribute dictionary;\n' - ' "__class__" is the instance’s class.\n' - '\n' - 'I/O objects (also known as file objects)\n' - ' A *file object* represents an open file. Various shortcuts are\n' - ' available to create file objects: the "open()" built-in ' - 'function,\n' - ' and also "os.popen()", "os.fdopen()", and the "makefile()" ' - 'method\n' - ' of socket objects (and perhaps by other functions or methods\n' - ' provided by extension modules).\n' - '\n' - ' The objects "sys.stdin", "sys.stdout" and "sys.stderr" are\n' - ' initialized to file objects corresponding to the interpreter’s\n' - ' standard input, output and error streams; they are all open in ' - 'text\n' - ' mode and therefore follow the interface defined by the\n' - ' "io.TextIOBase" abstract class.\n' - '\n' - 'Internal types\n' - ' A few types used internally by the interpreter are exposed to ' - 'the\n' - ' user. Their definitions may change with future versions of the\n' - ' interpreter, but they are mentioned here for completeness.\n' - '\n' - ' Code objects\n' - ' Code objects represent *byte-compiled* executable Python ' - 'code,\n' - ' or *bytecode*. The difference between a code object and a\n' - ' function object is that the function object contains an ' - 'explicit\n' - ' reference to the function’s globals (the module in which it ' - 'was\n' - ' defined), while a code object contains no context; also the\n' - ' default argument values are stored in the function object, ' - 'not\n' - ' in the code object (because they represent values calculated ' - 'at\n' - ' run-time). Unlike function objects, code objects are ' - 'immutable\n' - ' and contain no references (directly or indirectly) to ' - 'mutable\n' - ' objects.\n' - '\n' - ' Special read-only attributes: "co_name" gives the function ' - 'name;\n' - ' "co_argcount" is the number of positional arguments ' - '(including\n' - ' arguments with default values); "co_nlocals" is the number ' - 'of\n' - ' local variables used by the function (including arguments);\n' - ' "co_varnames" is a tuple containing the names of the local\n' - ' variables (starting with the argument names); "co_cellvars" ' - 'is a\n' - ' tuple containing the names of local variables that are\n' - ' referenced by nested functions; "co_freevars" is a tuple\n' - ' containing the names of free variables; "co_code" is a ' - 'string\n' - ' representing the sequence of bytecode instructions; ' - '"co_consts"\n' - ' is a tuple containing the literals used by the bytecode;\n' - ' "co_names" is a tuple containing the names used by the ' - 'bytecode;\n' - ' "co_filename" is the filename from which the code was ' - 'compiled;\n' - ' "co_firstlineno" is the first line number of the function;\n' - ' "co_lnotab" is a string encoding the mapping from bytecode\n' - ' offsets to line numbers (for details see the source code of ' - 'the\n' - ' interpreter); "co_stacksize" is the required stack size\n' - ' (including local variables); "co_flags" is an integer ' - 'encoding a\n' - ' number of flags for the interpreter.\n' - '\n' - ' The following flag bits are defined for "co_flags": bit ' - '"0x04"\n' - ' is set if the function uses the "*arguments" syntax to accept ' - 'an\n' - ' arbitrary number of positional arguments; bit "0x08" is set ' - 'if\n' - ' the function uses the "**keywords" syntax to accept ' - 'arbitrary\n' - ' keyword arguments; bit "0x20" is set if the function is a\n' - ' generator.\n' - '\n' - ' Future feature declarations ("from __future__ import ' - 'division")\n' - ' also use bits in "co_flags" to indicate whether a code ' - 'object\n' - ' was compiled with a particular feature enabled: bit "0x2000" ' - 'is\n' - ' set if the function was compiled with future division ' - 'enabled;\n' - ' bits "0x10" and "0x1000" were used in earlier versions of\n' - ' Python.\n' - '\n' - ' Other bits in "co_flags" are reserved for internal use.\n' - '\n' - ' If a code object represents a function, the first item in\n' - ' "co_consts" is the documentation string of the function, or\n' - ' "None" if undefined.\n' - '\n' - ' Frame objects\n' - ' Frame objects represent execution frames. They may occur in\n' - ' traceback objects (see below).\n' - '\n' - ' Special read-only attributes: "f_back" is to the previous ' - 'stack\n' - ' frame (towards the caller), or "None" if this is the bottom\n' - ' stack frame; "f_code" is the code object being executed in ' - 'this\n' - ' frame; "f_locals" is the dictionary used to look up local\n' - ' variables; "f_globals" is used for global variables;\n' - ' "f_builtins" is used for built-in (intrinsic) names; ' - '"f_lasti"\n' - ' gives the precise instruction (this is an index into the\n' - ' bytecode string of the code object).\n' - '\n' - ' Special writable attributes: "f_trace", if not "None", is a\n' - ' function called at the start of each source code line (this ' - 'is\n' - ' used by the debugger); "f_lineno" is the current line number ' - 'of\n' - ' the frame — writing to this from within a trace function ' - 'jumps\n' - ' to the given line (only for the bottom-most frame). A ' - 'debugger\n' - ' can implement a Jump command (aka Set Next Statement) by ' - 'writing\n' - ' to f_lineno.\n' - '\n' - ' Frame objects support one method:\n' - '\n' - ' frame.clear()\n' - '\n' - ' This method clears all references to local variables held ' - 'by\n' - ' the frame. Also, if the frame belonged to a generator, ' - 'the\n' - ' generator is finalized. This helps break reference ' - 'cycles\n' - ' involving frame objects (for example when catching an\n' - ' exception and storing its traceback for later use).\n' - '\n' - ' "RuntimeError" is raised if the frame is currently ' - 'executing.\n' - '\n' - ' New in version 3.4.\n' - '\n' - ' Traceback objects\n' - ' Traceback objects represent a stack trace of an exception. ' - 'A\n' - ' traceback object is created when an exception occurs. When ' - 'the\n' - ' search for an exception handler unwinds the execution stack, ' - 'at\n' - ' each unwound level a traceback object is inserted in front ' - 'of\n' - ' the current traceback. When an exception handler is ' - 'entered,\n' - ' the stack trace is made available to the program. (See ' - 'section\n' - ' The try statement.) It is accessible as the third item of ' - 'the\n' - ' tuple returned by "sys.exc_info()". When the program contains ' - 'no\n' - ' suitable handler, the stack trace is written (nicely ' - 'formatted)\n' - ' to the standard error stream; if the interpreter is ' - 'interactive,\n' - ' it is also made available to the user as ' - '"sys.last_traceback".\n' - '\n' - ' Special read-only attributes: "tb_next" is the next level in ' - 'the\n' - ' stack trace (towards the frame where the exception occurred), ' - 'or\n' - ' "None" if there is no next level; "tb_frame" points to the\n' - ' execution frame of the current level; "tb_lineno" gives the ' - 'line\n' - ' number where the exception occurred; "tb_lasti" indicates ' - 'the\n' - ' precise instruction. The line number and last instruction ' - 'in\n' - ' the traceback may differ from the line number of its frame\n' - ' object if the exception occurred in a "try" statement with ' - 'no\n' - ' matching except clause or with a finally clause.\n' - '\n' - ' Slice objects\n' - ' Slice objects are used to represent slices for ' - '"__getitem__()"\n' - ' methods. They are also created by the built-in "slice()"\n' - ' function.\n' - '\n' - ' Special read-only attributes: "start" is the lower bound; ' - '"stop"\n' - ' is the upper bound; "step" is the step value; each is "None" ' - 'if\n' - ' omitted. These attributes can have any type.\n' - '\n' - ' Slice objects support one method:\n' - '\n' - ' slice.indices(self, length)\n' - '\n' - ' This method takes a single integer argument *length* and\n' - ' computes information about the slice that the slice ' - 'object\n' - ' would describe if applied to a sequence of *length* ' - 'items.\n' - ' It returns a tuple of three integers; respectively these ' - 'are\n' - ' the *start* and *stop* indices and the *step* or stride\n' - ' length of the slice. Missing or out-of-bounds indices are\n' - ' handled in a manner consistent with regular slices.\n' - '\n' - ' Static method objects\n' - ' Static method objects provide a way of defeating the\n' - ' transformation of function objects to method objects ' - 'described\n' - ' above. A static method object is a wrapper around any other\n' - ' object, usually a user-defined method object. When a static\n' - ' method object is retrieved from a class or a class instance, ' - 'the\n' - ' object actually returned is the wrapped object, which is not\n' - ' subject to any further transformation. Static method objects ' - 'are\n' - ' not themselves callable, although the objects they wrap ' - 'usually\n' - ' are. Static method objects are created by the built-in\n' - ' "staticmethod()" constructor.\n' - '\n' - ' Class method objects\n' - ' A class method object, like a static method object, is a ' - 'wrapper\n' - ' around another object that alters the way in which that ' - 'object\n' - ' is retrieved from classes and class instances. The behaviour ' - 'of\n' - ' class method objects upon such retrieval is described above,\n' - ' under “User-defined methods”. Class method objects are ' - 'created\n' - ' by the built-in "classmethod()" constructor.\n', - 'typesfunctions': 'Functions\n' - '*********\n' - '\n' - 'Function objects are created by function definitions. The ' - 'only\n' - 'operation on a function object is to call it: ' - '"func(argument-list)".\n' - '\n' - 'There are really two flavors of function objects: built-in ' - 'functions\n' - 'and user-defined functions. Both support the same ' - 'operation (to call\n' - 'the function), but the implementation is different, hence ' - 'the\n' - 'different object types.\n' + 'is semantically equivalent to:\n' + '\n' \ + ' manager = (EXPRESSION)\n' + ' enter = type(manager).__enter__\n' + ' exit = type(manager).__exit__\n' \ + ' value = enter(manager)\n' + '\n' + ' try:\n' + ' TARGET = value\n' + ' SUITE\n' \ + ' except:\n' + ' if not exit(manager, *sys.exc_info()):\n' + ' raise\n' + ' else:\n' + ' exit(manager, None, None, None)\n' + '\n' + 'With more than one item, the context managers are processed as if\n' + 'multiple "with" statements were nested:\n' + '\n' + ' with A() as a, B() as b:\n' \ + ' SUITE\n' + '\n' + 'is semantically equivalent to:\n' + '\n' + ' with A() as a:\n' + ' with B() as b:\n' + ' SUITE\n' + '\n' + 'You can also write multi-item context managers in multiple lines if\n' \ + 'the items are surrounded by parentheses. For example:\n' + '\n' \ + ' with (\n' \ + ' A() as a,\n' + ' B() as b,\n' + ' ):\n' + ' SUITE\n' + '\n' \ + 'Changed in version 3.1: Support for multiple context expressions.\n' + '\n' + 'Changed in version 3.10: Support for using grouping parentheses to\n' + 'break the statement in multiple lines.\n' + '\n' + 'See also:\n' + '\n' + ' **PEP 343** - The “with” statement\n' + ' The specification, background, and examples for the Python ' \ + '"with"\n' + ' statement.\n', + 'yield': 'The "yield" statement\n' + '*********************\n' + '\n' \ + ' yield_stmt ::= yield_expression\n' '\n' - 'See Function definitions for more information.\n', - 'typesmapping': 'Mapping Types — "dict"\n' - '**********************\n' - '\n' - 'A *mapping* object maps *hashable* values to arbitrary ' - 'objects.\n' - 'Mappings are mutable objects. There is currently only one ' - 'standard\n' - 'mapping type, the *dictionary*. (For other containers see ' - 'the built-\n' - 'in "list", "set", and "tuple" classes, and the "collections" ' - 'module.)\n' - '\n' - 'A dictionary’s keys are *almost* arbitrary values. Values ' - 'that are\n' - 'not *hashable*, that is, values containing lists, ' - 'dictionaries or\n' - 'other mutable types (that are compared by value rather than ' - 'by object\n' - 'identity) may not be used as keys. Numeric types used for ' - 'keys obey\n' - 'the normal rules for numeric comparison: if two numbers ' - 'compare equal\n' - '(such as "1" and "1.0") then they can be used ' - 'interchangeably to index\n' - 'the same dictionary entry. (Note however, that since ' - 'computers store\n' - 'floating-point numbers as approximations it is usually ' - 'unwise to use\n' - 'them as dictionary keys.)\n' - '\n' - 'Dictionaries can be created by placing a comma-separated ' - 'list of "key:\n' - 'value" pairs within braces, for example: "{\'jack\': 4098, ' - "'sjoerd':\n" - '4127}" or "{4098: \'jack\', 4127: \'sjoerd\'}", or by the ' - '"dict"\n' - 'constructor.\n' - '\n' - 'class dict(**kwarg)\n' - 'class dict(mapping, **kwarg)\n' - 'class dict(iterable, **kwarg)\n' - '\n' - ' Return a new dictionary initialized from an optional ' - 'positional\n' - ' argument and a possibly empty set of keyword arguments.\n' - '\n' - ' If no positional argument is given, an empty dictionary ' - 'is created.\n' - ' If a positional argument is given and it is a mapping ' - 'object, a\n' - ' dictionary is created with the same key-value pairs as ' - 'the mapping\n' - ' object. Otherwise, the positional argument must be an ' - '*iterable*\n' - ' object. Each item in the iterable must itself be an ' - 'iterable with\n' - ' exactly two objects. The first object of each item ' - 'becomes a key\n' - ' in the new dictionary, and the second object the ' - 'corresponding\n' - ' value. If a key occurs more than once, the last value ' - 'for that key\n' - ' becomes the corresponding value in the new dictionary.\n' - '\n' - ' If keyword arguments are given, the keyword arguments and ' - 'their\n' - ' values are added to the dictionary created from the ' - 'positional\n' - ' argument. If a key being added is already present, the ' - 'value from\n' - ' the keyword argument replaces the value from the ' - 'positional\n' - ' argument.\n' - '\n' - ' To illustrate, the following examples all return a ' - 'dictionary equal\n' - ' to "{"one": 1, "two": 2, "three": 3}":\n' - '\n' - ' >>> a = dict(one=1, two=2, three=3)\n' - " >>> b = {'one': 1, 'two': 2, 'three': 3}\n" - " >>> c = dict(zip(['one', 'two', 'three'], [1, 2, 3]))\n" - " >>> d = dict([('two', 2), ('one', 1), ('three', 3)])\n" - " >>> e = dict({'three': 3, 'one': 1, 'two': 2})\n" - ' >>> a == b == c == d == e\n' - ' True\n' - '\n' - ' Providing keyword arguments as in the first example only ' - 'works for\n' - ' keys that are valid Python identifiers. Otherwise, any ' - 'valid keys\n' - ' can be used.\n' - '\n' - ' These are the operations that dictionaries support (and ' - 'therefore,\n' - ' custom mapping types should support too):\n' - '\n' - ' len(d)\n' - '\n' - ' Return the number of items in the dictionary *d*.\n' - '\n' - ' d[key]\n' - '\n' - ' Return the item of *d* with key *key*. Raises a ' - '"KeyError" if\n' - ' *key* is not in the map.\n' - '\n' - ' If a subclass of dict defines a method "__missing__()" ' - 'and *key*\n' - ' is not present, the "d[key]" operation calls that ' - 'method with\n' - ' the key *key* as argument. The "d[key]" operation ' - 'then returns\n' - ' or raises whatever is returned or raised by the\n' - ' "__missing__(key)" call. No other operations or ' - 'methods invoke\n' - ' "__missing__()". If "__missing__()" is not defined, ' - '"KeyError"\n' - ' is raised. "__missing__()" must be a method; it cannot ' - 'be an\n' - ' instance variable:\n' - '\n' - ' >>> class Counter(dict):\n' - ' ... def __missing__(self, key):\n' - ' ... return 0\n' - ' >>> c = Counter()\n' - " >>> c['red']\n" - ' 0\n' - " >>> c['red'] += 1\n" - " >>> c['red']\n" - ' 1\n' - '\n' - ' The example above shows part of the implementation of\n' - ' "collections.Counter". A different "__missing__" ' - 'method is used\n' - ' by "collections.defaultdict".\n' - '\n' - ' d[key] = value\n' - '\n' - ' Set "d[key]" to *value*.\n' - '\n' - ' del d[key]\n' - '\n' - ' Remove "d[key]" from *d*. Raises a "KeyError" if ' - '*key* is not\n' - ' in the map.\n' - '\n' - ' key in d\n' - '\n' - ' Return "True" if *d* has a key *key*, else "False".\n' - '\n' - ' key not in d\n' - '\n' - ' Equivalent to "not key in d".\n' - '\n' - ' iter(d)\n' - '\n' - ' Return an iterator over the keys of the dictionary. ' - 'This is a\n' - ' shortcut for "iter(d.keys())".\n' - '\n' - ' clear()\n' - '\n' - ' Remove all items from the dictionary.\n' - '\n' - ' copy()\n' - '\n' - ' Return a shallow copy of the dictionary.\n' - '\n' - ' classmethod fromkeys(seq[, value])\n' - '\n' - ' Create a new dictionary with keys from *seq* and ' - 'values set to\n' - ' *value*.\n' - '\n' - ' "fromkeys()" is a class method that returns a new ' - 'dictionary.\n' - ' *value* defaults to "None".\n' - '\n' - ' get(key[, default])\n' - '\n' - ' Return the value for *key* if *key* is in the ' - 'dictionary, else\n' - ' *default*. If *default* is not given, it defaults to ' - '"None", so\n' - ' that this method never raises a "KeyError".\n' - '\n' - ' items()\n' - '\n' - ' Return a new view of the dictionary’s items ("(key, ' - 'value)"\n' - ' pairs). See the documentation of view objects.\n' - '\n' - ' keys()\n' - '\n' - ' Return a new view of the dictionary’s keys. See the\n' - ' documentation of view objects.\n' - '\n' - ' pop(key[, default])\n' - '\n' - ' If *key* is in the dictionary, remove it and return ' - 'its value,\n' - ' else return *default*. If *default* is not given and ' - '*key* is\n' - ' not in the dictionary, a "KeyError" is raised.\n' - '\n' - ' popitem()\n' - '\n' - ' Remove and return an arbitrary "(key, value)" pair ' - 'from the\n' - ' dictionary.\n' - '\n' - ' "popitem()" is useful to destructively iterate over a\n' - ' dictionary, as often used in set algorithms. If the ' - 'dictionary\n' - ' is empty, calling "popitem()" raises a "KeyError".\n' - '\n' - ' setdefault(key[, default])\n' - '\n' - ' If *key* is in the dictionary, return its value. If ' - 'not, insert\n' - ' *key* with a value of *default* and return *default*. ' - '*default*\n' - ' defaults to "None".\n' - '\n' - ' update([other])\n' - '\n' - ' Update the dictionary with the key/value pairs from ' - '*other*,\n' - ' overwriting existing keys. Return "None".\n' - '\n' - ' "update()" accepts either another dictionary object or ' - 'an\n' - ' iterable of key/value pairs (as tuples or other ' - 'iterables of\n' - ' length two). If keyword arguments are specified, the ' - 'dictionary\n' - ' is then updated with those key/value pairs: ' - '"d.update(red=1,\n' - ' blue=2)".\n' - '\n' - ' values()\n' - '\n' - ' Return a new view of the dictionary’s values. See ' - 'the\n' - ' documentation of view objects.\n' - '\n' - ' Dictionaries compare equal if and only if they have the ' - 'same "(key,\n' - ' value)" pairs. Order comparisons (‘<’, ‘<=’, ‘>=’, ‘>’) ' - 'raise\n' - ' "TypeError".\n' - '\n' - 'See also: "types.MappingProxyType" can be used to create a ' - 'read-only\n' - ' view of a "dict".\n' - '\n' - '\n' - 'Dictionary view objects\n' - '=======================\n' - '\n' - 'The objects returned by "dict.keys()", "dict.values()" and\n' - '"dict.items()" are *view objects*. They provide a dynamic ' - 'view on the\n' - 'dictionary’s entries, which means that when the dictionary ' - 'changes,\n' - 'the view reflects these changes.\n' - '\n' - 'Dictionary views can be iterated over to yield their ' - 'respective data,\n' - 'and support membership tests:\n' - '\n' - 'len(dictview)\n' - '\n' - ' Return the number of entries in the dictionary.\n' - '\n' - 'iter(dictview)\n' - '\n' - ' Return an iterator over the keys, values or items ' - '(represented as\n' - ' tuples of "(key, value)") in the dictionary.\n' - '\n' - ' Keys and values are iterated over in an arbitrary order ' - 'which is\n' - ' non-random, varies across Python implementations, and ' - 'depends on\n' - ' the dictionary’s history of insertions and deletions. If ' - 'keys,\n' - ' values and items views are iterated over with no ' - 'intervening\n' - ' modifications to the dictionary, the order of items will ' - 'directly\n' - ' correspond. This allows the creation of "(value, key)" ' - 'pairs using\n' - ' "zip()": "pairs = zip(d.values(), d.keys())". Another ' - 'way to\n' - ' create the same list is "pairs = [(v, k) for (k, v) in ' - 'd.items()]".\n' - '\n' - ' Iterating views while adding or deleting entries in the ' - 'dictionary\n' - ' may raise a "RuntimeError" or fail to iterate over all ' - 'entries.\n' - '\n' - 'x in dictview\n' - '\n' - ' Return "True" if *x* is in the underlying dictionary’s ' - 'keys, values\n' - ' or items (in the latter case, *x* should be a "(key, ' - 'value)"\n' - ' tuple).\n' - '\n' - 'Keys views are set-like since their entries are unique and ' - 'hashable.\n' - 'If all values are hashable, so that "(key, value)" pairs are ' - 'unique\n' - 'and hashable, then the items view is also set-like. (Values ' - 'views are\n' - 'not treated as set-like since the entries are generally not ' - 'unique.)\n' - 'For set-like views, all of the operations defined for the ' - 'abstract\n' - 'base class "collections.abc.Set" are available (for example, ' - '"==",\n' - '"<", or "^").\n' - '\n' - 'An example of dictionary view usage:\n' - '\n' - " >>> dishes = {'eggs': 2, 'sausage': 1, 'bacon': 1, " - "'spam': 500}\n" - ' >>> keys = dishes.keys()\n' - ' >>> values = dishes.values()\n' - '\n' - ' >>> # iteration\n' - ' >>> n = 0\n' - ' >>> for val in values:\n' - ' ... n += val\n' - ' >>> print(n)\n' - ' 504\n' - '\n' - ' >>> # keys and values are iterated over in the same ' - 'order\n' - ' >>> list(keys)\n' - " ['eggs', 'bacon', 'sausage', 'spam']\n" - ' >>> list(values)\n' - ' [2, 1, 1, 500]\n' - '\n' - ' >>> # view objects are dynamic and reflect dict changes\n' - " >>> del dishes['eggs']\n" - " >>> del dishes['sausage']\n" - ' >>> list(keys)\n' - " ['spam', 'bacon']\n" - '\n' - ' >>> # set operations\n' - " >>> keys & {'eggs', 'bacon', 'salad'}\n" - " {'bacon'}\n" - " >>> keys ^ {'sausage', 'juice'}\n" - " {'juice', 'sausage', 'bacon', 'spam'}\n", - 'typesmethods': 'Methods\n' - '*******\n' - '\n' - 'Methods are functions that are called using the attribute ' - 'notation.\n' - 'There are two flavors: built-in methods (such as "append()" ' - 'on lists)\n' - 'and class instance methods. Built-in methods are described ' - 'with the\n' - 'types that support them.\n' - '\n' - 'If you access a method (a function defined in a class ' - 'namespace)\n' - 'through an instance, you get a special object: a *bound ' - 'method* (also\n' - 'called *instance method*) object. When called, it will add ' - 'the "self"\n' - 'argument to the argument list. Bound methods have two ' - 'special read-\n' - 'only attributes: "m.__self__" is the object on which the ' - 'method\n' - 'operates, and "m.__func__" is the function implementing the ' - 'method.\n' - 'Calling "m(arg-1, arg-2, ..., arg-n)" is completely ' - 'equivalent to\n' - 'calling "m.__func__(m.__self__, arg-1, arg-2, ..., arg-n)".\n' - '\n' - 'Like function objects, bound method objects support getting ' - 'arbitrary\n' - 'attributes. However, since method attributes are actually ' - 'stored on\n' - 'the underlying function object ("meth.__func__"), setting ' - 'method\n' - 'attributes on bound methods is disallowed. Attempting to ' - 'set an\n' - 'attribute on a method results in an "AttributeError" being ' - 'raised. In\n' - 'order to set a method attribute, you need to explicitly set ' - 'it on the\n' - 'underlying function object:\n' - '\n' - ' >>> class C:\n' - ' ... def method(self):\n' - ' ... pass\n' - ' ...\n' - ' >>> c = C()\n' - " >>> c.method.whoami = 'my name is method' # can't set on " - 'the method\n' - ' Traceback (most recent call last):\n' - ' File "", line 1, in \n' - " AttributeError: 'method' object has no attribute " - "'whoami'\n" - " >>> c.method.__func__.whoami = 'my name is method'\n" - ' >>> c.method.whoami\n' - " 'my name is method'\n" - '\n' - 'See The standard type hierarchy for more information.\n', - 'typesmodules': 'Modules\n' - '*******\n' - '\n' - 'The only special operation on a module is attribute access: ' - '"m.name",\n' - 'where *m* is a module and *name* accesses a name defined in ' - '*m*’s\n' - 'symbol table. Module attributes can be assigned to. (Note ' - 'that the\n' - '"import" statement is not, strictly speaking, an operation ' - 'on a module\n' - 'object; "import foo" does not require a module object named ' - '*foo* to\n' - 'exist, rather it requires an (external) *definition* for a ' - 'module\n' - 'named *foo* somewhere.)\n' - '\n' - 'A special attribute of every module is "__dict__". This is ' - 'the\n' - 'dictionary containing the module’s symbol table. Modifying ' - 'this\n' - 'dictionary will actually change the module’s symbol table, ' - 'but direct\n' - 'assignment to the "__dict__" attribute is not possible (you ' - 'can write\n' - '"m.__dict__[\'a\'] = 1", which defines "m.a" to be "1", but ' - 'you can’t\n' - 'write "m.__dict__ = {}"). Modifying "__dict__" directly is ' - 'not\n' - 'recommended.\n' - '\n' - 'Modules built into the interpreter are written like this: ' - '"". If loaded from a file, they are ' - 'written as\n' - '"".\n', - 'typesseq': 'Sequence Types — "list", "tuple", "range"\n' - '*****************************************\n' - '\n' - 'There are three basic sequence types: lists, tuples, and range\n' - 'objects. Additional sequence types tailored for processing of ' - 'binary\n' - 'data and text strings are described in dedicated sections.\n' - '\n' - '\n' - 'Common Sequence Operations\n' - '==========================\n' - '\n' - 'The operations in the following table are supported by most ' - 'sequence\n' - 'types, both mutable and immutable. The ' - '"collections.abc.Sequence" ABC\n' - 'is provided to make it easier to correctly implement these ' - 'operations\n' - 'on custom sequence types.\n' - '\n' - 'This table lists the sequence operations sorted in ascending ' - 'priority.\n' - 'In the table, *s* and *t* are sequences of the same type, *n*, ' - '*i*,\n' - '*j* and *k* are integers and *x* is an arbitrary object that ' - 'meets any\n' - 'type and value restrictions imposed by *s*.\n' - '\n' - 'The "in" and "not in" operations have the same priorities as ' - 'the\n' - 'comparison operations. The "+" (concatenation) and "*" ' - '(repetition)\n' - 'operations have the same priority as the corresponding numeric\n' - 'operations. [3]\n' - '\n' - '+----------------------------+----------------------------------+------------+\n' - '| Operation | Result ' - '| Notes |\n' - '+============================+==================================+============+\n' - '| "x in s" | "True" if an item of *s* is ' - '| (1) |\n' - '| | equal to *x*, else "False" ' - '| |\n' - '+----------------------------+----------------------------------+------------+\n' - '| "x not in s" | "False" if an item of *s* is ' - '| (1) |\n' - '| | equal to *x*, else "True" ' - '| |\n' - '+----------------------------+----------------------------------+------------+\n' - '| "s + t" | the concatenation of *s* and *t* ' - '| (6)(7) |\n' - '+----------------------------+----------------------------------+------------+\n' - '| "s * n" or "n * s" | equivalent to adding *s* to ' - '| (2)(7) |\n' - '| | itself *n* times ' - '| |\n' - '+----------------------------+----------------------------------+------------+\n' - '| "s[i]" | *i*th item of *s*, origin 0 ' - '| (3) |\n' - '+----------------------------+----------------------------------+------------+\n' - '| "s[i:j]" | slice of *s* from *i* to *j* ' - '| (3)(4) |\n' - '+----------------------------+----------------------------------+------------+\n' - '| "s[i:j:k]" | slice of *s* from *i* to *j* ' - '| (3)(5) |\n' - '| | with step *k* ' - '| |\n' - '+----------------------------+----------------------------------+------------+\n' - '| "len(s)" | length of *s* ' - '| |\n' - '+----------------------------+----------------------------------+------------+\n' - '| "min(s)" | smallest item of *s* ' - '| |\n' - '+----------------------------+----------------------------------+------------+\n' - '| "max(s)" | largest item of *s* ' - '| |\n' - '+----------------------------+----------------------------------+------------+\n' - '| "s.index(x[, i[, j]])" | index of the first occurrence of ' - '| (8) |\n' - '| | *x* in *s* (at or after index ' - '| |\n' - '| | *i* and before index *j*) ' - '| |\n' - '+----------------------------+----------------------------------+------------+\n' - '| "s.count(x)" | total number of occurrences of ' - '| |\n' - '| | *x* in *s* ' - '| |\n' - '+----------------------------+----------------------------------+------------+\n' - '\n' - 'Sequences of the same type also support comparisons. In ' - 'particular,\n' - 'tuples and lists are compared lexicographically by comparing\n' - 'corresponding elements. This means that to compare equal, every\n' - 'element must compare equal and the two sequences must be of the ' - 'same\n' - 'type and have the same length. (For full details see ' - 'Comparisons in\n' - 'the language reference.)\n' - '\n' - 'Notes:\n' - '\n' - '1. While the "in" and "not in" operations are used only for ' - 'simple\n' - ' containment testing in the general case, some specialised ' - 'sequences\n' - ' (such as "str", "bytes" and "bytearray") also use them for\n' - ' subsequence testing:\n' - '\n' - ' >>> "gg" in "eggs"\n' - ' True\n' - '\n' - '2. Values of *n* less than "0" are treated as "0" (which yields ' - 'an\n' - ' empty sequence of the same type as *s*). Note that items in ' - 'the\n' - ' sequence *s* are not copied; they are referenced multiple ' - 'times.\n' - ' This often haunts new Python programmers; consider:\n' - '\n' - ' >>> lists = [[]] * 3\n' - ' >>> lists\n' - ' [[], [], []]\n' - ' >>> lists[0].append(3)\n' - ' >>> lists\n' - ' [[3], [3], [3]]\n' - '\n' - ' What has happened is that "[[]]" is a one-element list ' - 'containing\n' - ' an empty list, so all three elements of "[[]] * 3" are ' - 'references\n' - ' to this single empty list. Modifying any of the elements of\n' - ' "lists" modifies this single list. You can create a list of\n' - ' different lists this way:\n' - '\n' - ' >>> lists = [[] for i in range(3)]\n' - ' >>> lists[0].append(3)\n' - ' >>> lists[1].append(5)\n' - ' >>> lists[2].append(7)\n' - ' >>> lists\n' - ' [[3], [5], [7]]\n' - '\n' - ' Further explanation is available in the FAQ entry How do I ' - 'create a\n' - ' multidimensional list?.\n' - '\n' - '3. If *i* or *j* is negative, the index is relative to the end ' - 'of\n' - ' sequence *s*: "len(s) + i" or "len(s) + j" is substituted. ' - 'But\n' - ' note that "-0" is still "0".\n' - '\n' - '4. The slice of *s* from *i* to *j* is defined as the sequence ' - 'of\n' - ' items with index *k* such that "i <= k < j". If *i* or *j* ' - 'is\n' - ' greater than "len(s)", use "len(s)". If *i* is omitted or ' - '"None",\n' - ' use "0". If *j* is omitted or "None", use "len(s)". If *i* ' - 'is\n' - ' greater than or equal to *j*, the slice is empty.\n' - '\n' - '5. The slice of *s* from *i* to *j* with step *k* is defined as ' - 'the\n' - ' sequence of items with index "x = i + n*k" such that "0 <= n ' - '<\n' - ' (j-i)/k". In other words, the indices are "i", "i+k", ' - '"i+2*k",\n' - ' "i+3*k" and so on, stopping when *j* is reached (but never\n' - ' including *j*). When *k* is positive, *i* and *j* are ' - 'reduced to\n' - ' "len(s)" if they are greater. When *k* is negative, *i* and ' - '*j* are\n' - ' reduced to "len(s) - 1" if they are greater. If *i* or *j* ' - 'are\n' - ' omitted or "None", they become “end” values (which end ' - 'depends on\n' - ' the sign of *k*). Note, *k* cannot be zero. If *k* is ' - '"None", it\n' - ' is treated like "1".\n' - '\n' - '6. Concatenating immutable sequences always results in a new\n' - ' object. This means that building up a sequence by repeated\n' - ' concatenation will have a quadratic runtime cost in the ' - 'total\n' - ' sequence length. To get a linear runtime cost, you must ' - 'switch to\n' - ' one of the alternatives below:\n' - '\n' - ' * if concatenating "str" objects, you can build a list and ' - 'use\n' - ' "str.join()" at the end or else write to an "io.StringIO"\n' - ' instance and retrieve its value when complete\n' - '\n' - ' * if concatenating "bytes" objects, you can similarly use\n' - ' "bytes.join()" or "io.BytesIO", or you can do in-place\n' - ' concatenation with a "bytearray" object. "bytearray" ' - 'objects are\n' - ' mutable and have an efficient overallocation mechanism\n' - '\n' - ' * if concatenating "tuple" objects, extend a "list" instead\n' - '\n' - ' * for other types, investigate the relevant class ' - 'documentation\n' - '\n' - '7. Some sequence types (such as "range") only support item\n' - ' sequences that follow specific patterns, and hence don’t ' - 'support\n' - ' sequence concatenation or repetition.\n' - '\n' - '8. "index" raises "ValueError" when *x* is not found in *s*. ' - 'Not\n' - ' all implementations support passing the additional arguments ' - '*i*\n' - ' and *j*. These arguments allow efficient searching of ' - 'subsections\n' - ' of the sequence. Passing the extra arguments is roughly ' - 'equivalent\n' - ' to using "s[i:j].index(x)", only without copying any data and ' - 'with\n' - ' the returned index being relative to the start of the ' - 'sequence\n' - ' rather than the start of the slice.\n' - '\n' - '\n' - 'Immutable Sequence Types\n' - '========================\n' - '\n' - 'The only operation that immutable sequence types generally ' - 'implement\n' - 'that is not also implemented by mutable sequence types is ' - 'support for\n' - 'the "hash()" built-in.\n' - '\n' - 'This support allows immutable sequences, such as "tuple" ' - 'instances, to\n' - 'be used as "dict" keys and stored in "set" and "frozenset" ' - 'instances.\n' - '\n' - 'Attempting to hash an immutable sequence that contains ' - 'unhashable\n' - 'values will result in "TypeError".\n' - '\n' - '\n' - 'Mutable Sequence Types\n' - '======================\n' - '\n' - 'The operations in the following table are defined on mutable ' - 'sequence\n' - 'types. The "collections.abc.MutableSequence" ABC is provided to ' - 'make\n' - 'it easier to correctly implement these operations on custom ' - 'sequence\n' - 'types.\n' - '\n' - 'In the table *s* is an instance of a mutable sequence type, *t* ' - 'is any\n' - 'iterable object and *x* is an arbitrary object that meets any ' - 'type and\n' - 'value restrictions imposed by *s* (for example, "bytearray" ' - 'only\n' - 'accepts integers that meet the value restriction "0 <= x <= ' - '255").\n' - '\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| Operation | ' - 'Result | Notes |\n' - '+================================+==================================+=======================+\n' - '| "s[i] = x" | item *i* of *s* is replaced ' - 'by | |\n' - '| | ' - '*x* | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s[i:j] = t" | slice of *s* from *i* to *j* ' - 'is | |\n' - '| | replaced by the contents of ' - 'the | |\n' - '| | iterable ' - '*t* | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "del s[i:j]" | same as "s[i:j] = ' - '[]" | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s[i:j:k] = t" | the elements of "s[i:j:k]" ' - 'are | (1) |\n' - '| | replaced by those of ' - '*t* | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "del s[i:j:k]" | removes the elements ' - 'of | |\n' - '| | "s[i:j:k]" from the ' - 'list | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s.append(x)" | appends *x* to the end of ' - 'the | |\n' - '| | sequence (same ' - 'as | |\n' - '| | "s[len(s):len(s)] = ' - '[x]") | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s.clear()" | removes all items from *s* ' - '(same | (5) |\n' - '| | as "del ' - 's[:]") | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s.copy()" | creates a shallow copy of ' - '*s* | (5) |\n' - '| | (same as ' - '"s[:]") | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s.extend(t)" or "s += t" | extends *s* with the contents ' - 'of | |\n' - '| | *t* (for the most part the ' - 'same | |\n' - '| | as "s[len(s):len(s)] = ' - 't") | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s *= n" | updates *s* with its ' - 'contents | (6) |\n' - '| | repeated *n* ' - 'times | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s.insert(i, x)" | inserts *x* into *s* at ' - 'the | |\n' - '| | index given by *i* (same ' - 'as | |\n' - '| | "s[i:i] = ' - '[x]") | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s.pop([i])" | retrieves the item at *i* ' - 'and | (2) |\n' - '| | also removes it from ' - '*s* | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s.remove(x)" | remove the first item from ' - '*s* | (3) |\n' - '| | where "s[i] == ' - 'x" | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s.reverse()" | reverses the items of *s* ' - 'in | (4) |\n' - '| | ' - 'place | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '\n' - 'Notes:\n' - '\n' - '1. *t* must have the same length as the slice it is replacing.\n' - '\n' - '2. The optional argument *i* defaults to "-1", so that by ' - 'default\n' - ' the last item is removed and returned.\n' - '\n' - '3. "remove" raises "ValueError" when *x* is not found in *s*.\n' - '\n' - '4. The "reverse()" method modifies the sequence in place for\n' - ' economy of space when reversing a large sequence. To remind ' - 'users\n' - ' that it operates by side effect, it does not return the ' - 'reversed\n' - ' sequence.\n' - '\n' - '5. "clear()" and "copy()" are included for consistency with the\n' - ' interfaces of mutable containers that don’t support slicing\n' - ' operations (such as "dict" and "set")\n' - '\n' - ' New in version 3.3: "clear()" and "copy()" methods.\n' - '\n' - '6. The value *n* is an integer, or an object implementing\n' - ' "__index__()". Zero and negative values of *n* clear the ' - 'sequence.\n' - ' Items in the sequence are not copied; they are referenced ' - 'multiple\n' - ' times, as explained for "s * n" under Common Sequence ' - 'Operations.\n' - '\n' - '\n' - 'Lists\n' - '=====\n' - '\n' - 'Lists are mutable sequences, typically used to store collections ' - 'of\n' - 'homogeneous items (where the precise degree of similarity will ' - 'vary by\n' - 'application).\n' - '\n' - 'class list([iterable])\n' - '\n' - ' Lists may be constructed in several ways:\n' - '\n' - ' * Using a pair of square brackets to denote the empty list: ' - '"[]"\n' - '\n' - ' * Using square brackets, separating items with commas: ' - '"[a]",\n' - ' "[a, b, c]"\n' - '\n' - ' * Using a list comprehension: "[x for x in iterable]"\n' - '\n' - ' * Using the type constructor: "list()" or "list(iterable)"\n' - '\n' - ' The constructor builds a list whose items are the same and in ' - 'the\n' - ' same order as *iterable*’s items. *iterable* may be either ' - 'a\n' - ' sequence, a container that supports iteration, or an ' - 'iterator\n' - ' object. If *iterable* is already a list, a copy is made and\n' - ' returned, similar to "iterable[:]". For example, ' - '"list(\'abc\')"\n' - ' returns "[\'a\', \'b\', \'c\']" and "list( (1, 2, 3) )" ' - 'returns "[1, 2,\n' - ' 3]". If no argument is given, the constructor creates a new ' - 'empty\n' - ' list, "[]".\n' - '\n' - ' Many other operations also produce lists, including the ' - '"sorted()"\n' - ' built-in.\n' - '\n' - ' Lists implement all of the common and mutable sequence ' - 'operations.\n' - ' Lists also provide the following additional method:\n' - '\n' - ' sort(*, key=None, reverse=False)\n' - '\n' - ' This method sorts the list in place, using only "<" ' - 'comparisons\n' - ' between items. Exceptions are not suppressed - if any ' - 'comparison\n' - ' operations fail, the entire sort operation will fail (and ' - 'the\n' - ' list will likely be left in a partially modified state).\n' - '\n' - ' "sort()" accepts two arguments that can only be passed by\n' - ' keyword (keyword-only arguments):\n' - '\n' - ' *key* specifies a function of one argument that is used ' - 'to\n' - ' extract a comparison key from each list element (for ' - 'example,\n' - ' "key=str.lower"). The key corresponding to each item in ' - 'the list\n' - ' is calculated once and then used for the entire sorting ' - 'process.\n' - ' The default value of "None" means that list items are ' - 'sorted\n' - ' directly without calculating a separate key value.\n' - '\n' - ' The "functools.cmp_to_key()" utility is available to ' - 'convert a\n' - ' 2.x style *cmp* function to a *key* function.\n' - '\n' - ' *reverse* is a boolean value. If set to "True", then the ' - 'list\n' - ' elements are sorted as if each comparison were reversed.\n' - '\n' - ' This method modifies the sequence in place for economy of ' - 'space\n' - ' when sorting a large sequence. To remind users that it ' - 'operates\n' - ' by side effect, it does not return the sorted sequence ' - '(use\n' - ' "sorted()" to explicitly request a new sorted list ' - 'instance).\n' - '\n' - ' The "sort()" method is guaranteed to be stable. A sort ' - 'is\n' - ' stable if it guarantees not to change the relative order ' - 'of\n' - ' elements that compare equal — this is helpful for sorting ' - 'in\n' - ' multiple passes (for example, sort by department, then by ' - 'salary\n' - ' grade).\n' - '\n' - ' **CPython implementation detail:** While a list is being ' - 'sorted,\n' - ' the effect of attempting to mutate, or even inspect, the ' - 'list is\n' - ' undefined. The C implementation of Python makes the list ' - 'appear\n' - ' empty for the duration, and raises "ValueError" if it can ' - 'detect\n' - ' that the list has been mutated during a sort.\n' - '\n' - '\n' - 'Tuples\n' - '======\n' - '\n' - 'Tuples are immutable sequences, typically used to store ' - 'collections of\n' - 'heterogeneous data (such as the 2-tuples produced by the ' - '"enumerate()"\n' - 'built-in). Tuples are also used for cases where an immutable ' - 'sequence\n' - 'of homogeneous data is needed (such as allowing storage in a ' - '"set" or\n' - '"dict" instance).\n' - '\n' - 'class tuple([iterable])\n' - '\n' - ' Tuples may be constructed in a number of ways:\n' - '\n' - ' * Using a pair of parentheses to denote the empty tuple: ' - '"()"\n' - '\n' - ' * Using a trailing comma for a singleton tuple: "a," or ' - '"(a,)"\n' - '\n' - ' * Separating items with commas: "a, b, c" or "(a, b, c)"\n' - '\n' - ' * Using the "tuple()" built-in: "tuple()" or ' - '"tuple(iterable)"\n' - '\n' - ' The constructor builds a tuple whose items are the same and ' - 'in the\n' - ' same order as *iterable*’s items. *iterable* may be either ' - 'a\n' - ' sequence, a container that supports iteration, or an ' - 'iterator\n' - ' object. If *iterable* is already a tuple, it is returned\n' - ' unchanged. For example, "tuple(\'abc\')" returns "(\'a\', ' - '\'b\', \'c\')"\n' - ' and "tuple( [1, 2, 3] )" returns "(1, 2, 3)". If no argument ' - 'is\n' - ' given, the constructor creates a new empty tuple, "()".\n' - '\n' - ' Note that it is actually the comma which makes a tuple, not ' - 'the\n' - ' parentheses. The parentheses are optional, except in the ' - 'empty\n' - ' tuple case, or when they are needed to avoid syntactic ' - 'ambiguity.\n' - ' For example, "f(a, b, c)" is a function call with three ' - 'arguments,\n' - ' while "f((a, b, c))" is a function call with a 3-tuple as the ' - 'sole\n' - ' argument.\n' - '\n' - ' Tuples implement all of the common sequence operations.\n' - '\n' - 'For heterogeneous collections of data where access by name is ' - 'clearer\n' - 'than access by index, "collections.namedtuple()" may be a more\n' - 'appropriate choice than a simple tuple object.\n' - '\n' - '\n' - 'Ranges\n' - '======\n' - '\n' - 'The "range" type represents an immutable sequence of numbers and ' - 'is\n' - 'commonly used for looping a specific number of times in "for" ' - 'loops.\n' - '\n' - 'class range(stop)\n' - 'class range(start, stop[, step])\n' - '\n' - ' The arguments to the range constructor must be integers ' - '(either\n' - ' built-in "int" or any object that implements the "__index__"\n' - ' special method). If the *step* argument is omitted, it ' - 'defaults to\n' - ' "1". If the *start* argument is omitted, it defaults to "0". ' - 'If\n' - ' *step* is zero, "ValueError" is raised.\n' - '\n' - ' For a positive *step*, the contents of a range "r" are ' - 'determined\n' - ' by the formula "r[i] = start + step*i" where "i >= 0" and ' - '"r[i] <\n' - ' stop".\n' - '\n' - ' For a negative *step*, the contents of the range are still\n' - ' determined by the formula "r[i] = start + step*i", but the\n' - ' constraints are "i >= 0" and "r[i] > stop".\n' - '\n' - ' A range object will be empty if "r[0]" does not meet the ' - 'value\n' - ' constraint. Ranges do support negative indices, but these ' - 'are\n' - ' interpreted as indexing from the end of the sequence ' - 'determined by\n' - ' the positive indices.\n' - '\n' - ' Ranges containing absolute values larger than "sys.maxsize" ' - 'are\n' - ' permitted but some features (such as "len()") may raise\n' - ' "OverflowError".\n' - '\n' - ' Range examples:\n' - '\n' - ' >>> list(range(10))\n' - ' [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]\n' - ' >>> list(range(1, 11))\n' - ' [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]\n' - ' >>> list(range(0, 30, 5))\n' - ' [0, 5, 10, 15, 20, 25]\n' - ' >>> list(range(0, 10, 3))\n' - ' [0, 3, 6, 9]\n' - ' >>> list(range(0, -10, -1))\n' - ' [0, -1, -2, -3, -4, -5, -6, -7, -8, -9]\n' - ' >>> list(range(0))\n' - ' []\n' - ' >>> list(range(1, 0))\n' - ' []\n' - '\n' - ' Ranges implement all of the common sequence operations ' - 'except\n' - ' concatenation and repetition (due to the fact that range ' - 'objects\n' - ' can only represent sequences that follow a strict pattern ' - 'and\n' - ' repetition and concatenation will usually violate that ' - 'pattern).\n' - '\n' - ' start\n' - '\n' - ' The value of the *start* parameter (or "0" if the ' - 'parameter was\n' - ' not supplied)\n' - '\n' - ' stop\n' - '\n' - ' The value of the *stop* parameter\n' - '\n' - ' step\n' - '\n' - ' The value of the *step* parameter (or "1" if the parameter ' - 'was\n' - ' not supplied)\n' - '\n' - 'The advantage of the "range" type over a regular "list" or ' - '"tuple" is\n' - 'that a "range" object will always take the same (small) amount ' - 'of\n' - 'memory, no matter the size of the range it represents (as it ' - 'only\n' - 'stores the "start", "stop" and "step" values, calculating ' - 'individual\n' - 'items and subranges as needed).\n' - '\n' - 'Range objects implement the "collections.abc.Sequence" ABC, and\n' - 'provide features such as containment tests, element index ' - 'lookup,\n' - 'slicing and support for negative indices (see Sequence Types — ' - 'list,\n' - 'tuple, range):\n' - '\n' - '>>> r = range(0, 20, 2)\n' - '>>> r\n' - 'range(0, 20, 2)\n' - '>>> 11 in r\n' - 'False\n' - '>>> 10 in r\n' - 'True\n' - '>>> r.index(10)\n' - '5\n' - '>>> r[5]\n' - '10\n' - '>>> r[:5]\n' - 'range(0, 10, 2)\n' - '>>> r[-1]\n' - '18\n' - '\n' - 'Testing range objects for equality with "==" and "!=" compares ' - 'them as\n' - 'sequences. That is, two range objects are considered equal if ' - 'they\n' - 'represent the same sequence of values. (Note that two range ' - 'objects\n' - 'that compare equal might have different "start", "stop" and ' - '"step"\n' - 'attributes, for example "range(0) == range(2, 1, 3)" or ' - '"range(0, 3,\n' - '2) == range(0, 4, 2)".)\n' - '\n' - 'Changed in version 3.2: Implement the Sequence ABC. Support ' - 'slicing\n' - 'and negative indices. Test "int" objects for membership in ' - 'constant\n' - 'time instead of iterating through all items.\n' - '\n' - 'Changed in version 3.3: Define ‘==’ and ‘!=’ to compare range ' - 'objects\n' - 'based on the sequence of values they define (instead of ' - 'comparing\n' - 'based on object identity).\n' - '\n' - 'New in version 3.3: The "start", "stop" and "step" attributes.\n' - '\n' - 'See also:\n' - '\n' - ' * The linspace recipe shows how to implement a lazy version ' - 'of\n' - ' range suitable for floating point applications.\n', - 'typesseq-mutable': 'Mutable Sequence Types\n' - '**********************\n' - '\n' - 'The operations in the following table are defined on ' - 'mutable sequence\n' - 'types. The "collections.abc.MutableSequence" ABC is ' - 'provided to make\n' - 'it easier to correctly implement these operations on ' - 'custom sequence\n' - 'types.\n' - '\n' - 'In the table *s* is an instance of a mutable sequence ' - 'type, *t* is any\n' - 'iterable object and *x* is an arbitrary object that ' - 'meets any type and\n' - 'value restrictions imposed by *s* (for example, ' - '"bytearray" only\n' - 'accepts integers that meet the value restriction "0 <= x ' - '<= 255").\n' - '\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| Operation | ' - 'Result | Notes ' - '|\n' - '+================================+==================================+=======================+\n' - '| "s[i] = x" | item *i* of *s* is ' - 'replaced by | |\n' - '| | ' - '*x* | ' - '|\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s[i:j] = t" | slice of *s* from *i* ' - 'to *j* is | |\n' - '| | replaced by the ' - 'contents of the | |\n' - '| | iterable ' - '*t* | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "del s[i:j]" | same as "s[i:j] = ' - '[]" | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s[i:j:k] = t" | the elements of ' - '"s[i:j:k]" are | (1) |\n' - '| | replaced by those of ' - '*t* | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "del s[i:j:k]" | removes the elements ' - 'of | |\n' - '| | "s[i:j:k]" from the ' - 'list | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s.append(x)" | appends *x* to the ' - 'end of the | |\n' - '| | sequence (same ' - 'as | |\n' - '| | "s[len(s):len(s)] = ' - '[x]") | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s.clear()" | removes all items ' - 'from *s* (same | (5) |\n' - '| | as "del ' - 's[:]") | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s.copy()" | creates a shallow ' - 'copy of *s* | (5) |\n' - '| | (same as ' - '"s[:]") | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s.extend(t)" or "s += t" | extends *s* with the ' - 'contents of | |\n' - '| | *t* (for the most ' - 'part the same | |\n' - '| | as "s[len(s):len(s)] ' - '= t") | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s *= n" | updates *s* with its ' - 'contents | (6) |\n' - '| | repeated *n* ' - 'times | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s.insert(i, x)" | inserts *x* into *s* ' - 'at the | |\n' - '| | index given by *i* ' - '(same as | |\n' - '| | "s[i:i] = ' - '[x]") | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s.pop([i])" | retrieves the item at ' - '*i* and | (2) |\n' - '| | also removes it from ' - '*s* | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s.remove(x)" | remove the first item ' - 'from *s* | (3) |\n' - '| | where "s[i] == ' - 'x" | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s.reverse()" | reverses the items of ' - '*s* in | (4) |\n' - '| | ' - 'place | ' - '|\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '\n' - 'Notes:\n' - '\n' - '1. *t* must have the same length as the slice it is ' - 'replacing.\n' - '\n' - '2. The optional argument *i* defaults to "-1", so that ' - 'by default\n' - ' the last item is removed and returned.\n' - '\n' - '3. "remove" raises "ValueError" when *x* is not found in ' - '*s*.\n' - '\n' - '4. The "reverse()" method modifies the sequence in place ' - 'for\n' - ' economy of space when reversing a large sequence. To ' - 'remind users\n' - ' that it operates by side effect, it does not return ' - 'the reversed\n' - ' sequence.\n' - '\n' - '5. "clear()" and "copy()" are included for consistency ' - 'with the\n' - ' interfaces of mutable containers that don’t support ' - 'slicing\n' - ' operations (such as "dict" and "set")\n' - '\n' - ' New in version 3.3: "clear()" and "copy()" methods.\n' - '\n' - '6. The value *n* is an integer, or an object ' - 'implementing\n' - ' "__index__()". Zero and negative values of *n* clear ' - 'the sequence.\n' - ' Items in the sequence are not copied; they are ' - 'referenced multiple\n' - ' times, as explained for "s * n" under Common Sequence ' - 'Operations.\n', - 'unary': 'Unary arithmetic and bitwise operations\n' - '***************************************\n' - '\n' - 'All unary arithmetic and bitwise operations have the same ' - 'priority:\n' - '\n' - ' u_expr ::= power | "-" u_expr | "+" u_expr | "~" u_expr\n' - '\n' - 'The unary "-" (minus) operator yields the negation of its numeric\n' - 'argument.\n' - '\n' - 'The unary "+" (plus) operator yields its numeric argument ' - 'unchanged.\n' - '\n' - 'The unary "~" (invert) operator yields the bitwise inversion of ' - 'its\n' - 'integer argument. The bitwise inversion of "x" is defined as\n' - '"-(x+1)". It only applies to integral numbers.\n' - '\n' - 'In all three cases, if the argument does not have the proper type, ' - 'a\n' - '"TypeError" exception is raised.\n', - 'while': 'The "while" statement\n' - '*********************\n' - '\n' - 'The "while" statement is used for repeated execution as long as an\n' - 'expression is true:\n' - '\n' - ' while_stmt ::= "while" expression ":" suite\n' - ' ["else" ":" suite]\n' - '\n' - 'This repeatedly tests the expression and, if it is true, executes ' - 'the\n' - 'first suite; if the expression is false (which may be the first ' - 'time\n' - 'it is tested) the suite of the "else" clause, if present, is ' - 'executed\n' - 'and the loop terminates.\n' - '\n' - 'A "break" statement executed in the first suite terminates the ' - 'loop\n' - 'without executing the "else" clause’s suite. A "continue" ' - 'statement\n' - 'executed in the first suite skips the rest of the suite and goes ' - 'back\n' - 'to testing the expression.\n', - 'with': 'The "with" statement\n' - '********************\n' - '\n' - 'The "with" statement is used to wrap the execution of a block with\n' - 'methods defined by a context manager (see section With Statement\n' - 'Context Managers). This allows common "try"…"except"…"finally" ' - 'usage\n' - 'patterns to be encapsulated for convenient reuse.\n' - '\n' - ' with_stmt ::= "with" with_item ("," with_item)* ":" suite\n' - ' with_item ::= expression ["as" target]\n' - '\n' - 'The execution of the "with" statement with one “item” proceeds as\n' - 'follows:\n' - '\n' - '1. The context expression (the expression given in the "with_item")\n' - ' is evaluated to obtain a context manager.\n' - '\n' - '2. The context manager’s "__exit__()" is loaded for later use.\n' - '\n' - '3. The context manager’s "__enter__()" method is invoked.\n' - '\n' - '4. If a target was included in the "with" statement, the return\n' - ' value from "__enter__()" is assigned to it.\n' - '\n' - ' Note: The "with" statement guarantees that if the "__enter__()"\n' - ' method returns without an error, then "__exit__()" will always ' - 'be\n' - ' called. Thus, if an error occurs during the assignment to the\n' - ' target list, it will be treated the same as an error occurring\n' - ' within the suite would be. See step 6 below.\n' - '\n' - '5. The suite is executed.\n' - '\n' - '6. The context manager’s "__exit__()" method is invoked. If an\n' - ' exception caused the suite to be exited, its type, value, and\n' - ' traceback are passed as arguments to "__exit__()". Otherwise, ' - 'three\n' - ' "None" arguments are supplied.\n' - '\n' - ' If the suite was exited due to an exception, and the return ' - 'value\n' - ' from the "__exit__()" method was false, the exception is ' - 'reraised.\n' - ' If the return value was true, the exception is suppressed, and\n' - ' execution continues with the statement following the "with"\n' - ' statement.\n' - '\n' - ' If the suite was exited for any reason other than an exception, ' - 'the\n' - ' return value from "__exit__()" is ignored, and execution ' - 'proceeds\n' - ' at the normal location for the kind of exit that was taken.\n' - '\n' - 'With more than one item, the context managers are processed as if\n' - 'multiple "with" statements were nested:\n' - '\n' - ' with A() as a, B() as b:\n' - ' suite\n' - '\n' - 'is equivalent to\n' - '\n' - ' with A() as a:\n' - ' with B() as b:\n' - ' suite\n' - '\n' - 'Changed in version 3.1: Support for multiple context expressions.\n' - '\n' - 'See also:\n' - '\n' - ' **PEP 343** - The “with” statement\n' - ' The specification, background, and examples for the Python ' - '"with"\n' - ' statement.\n', - 'yield': 'The "yield" statement\n' - '*********************\n' - '\n' - ' yield_stmt ::= yield_expression\n' - '\n' - 'A "yield" statement is semantically equivalent to a yield ' - 'expression.\n' - 'The yield statement can be used to omit the parentheses that would\n' - 'otherwise be required in the equivalent yield expression ' - 'statement.\n' - 'For example, the yield statements\n' - '\n' - ' yield \n' - ' yield from \n' - '\n' - 'are equivalent to the yield expression statements\n' - '\n' - ' (yield )\n' - ' (yield from )\n' - '\n' - 'Yield expressions and statements are only used when defining a\n' - '*generator* function, and are only used in the body of the ' - 'generator\n' - 'function. Using yield in a function definition is sufficient to ' - 'cause\n' - 'that definition to create a generator function instead of a normal\n' - 'function.\n' - '\n' - 'For full details of "yield" semantics, refer to the Yield ' - 'expressions\n' - 'section.\n'} + 'A "yield" statement is semantically equivalent to a yield ' + 'expression.\n' + 'The "yield" statement can be used to omit the parentheses that ' + 'would\n' \ + 'otherwise be required in the equivalent yield expression ' + 'statement.\n' + 'For example, the yield statements\n' + '\n' + ' yield \n' + ' yield from \n' + '\n' + 'are equivalent to the yield expression statements\n' + '\n' + ' (yield )\n' + ' (yield from )\n' \ + '\n' + 'Yield expressions and statements are only used when defining a\n' + '*generator* function, and are only used in the body of the ' + 'generator\n' + 'function. Using "yield" in a function definition is sufficient to\n' + 'cause that definition to create a generator function instead of a\n' + 'normal function.\n' + '\n' + 'For full details of "yield" semantics, refer to the Yield ' + 'expressions\n' + 'section.\n'} \ No newline at end of file diff --git a/Lib/tarfile.py b/Lib/tarfile.py index dea150e8db..b893c52022 100755 --- a/Lib/tarfile.py +++ b/Lib/tarfile.py @@ -46,6 +46,7 @@ import struct import copy import re +import warnings try: import pwd @@ -57,19 +58,19 @@ grp = None # os.symlink on Windows prior to 6.0 raises NotImplementedError -symlink_exception = (AttributeError, NotImplementedError) -try: - # OSError (winerror=1314) will be raised if the caller does not hold the - # SeCreateSymbolicLinkPrivilege privilege - symlink_exception += (OSError,) -except NameError: - pass +# OSError (winerror=1314) will be raised if the caller does not hold the +# SeCreateSymbolicLinkPrivilege privilege +symlink_exception = (AttributeError, NotImplementedError, OSError) # from tarfile import * __all__ = ["TarFile", "TarInfo", "is_tarfile", "TarError", "ReadError", "CompressionError", "StreamError", "ExtractError", "HeaderError", "ENCODING", "USTAR_FORMAT", "GNU_FORMAT", "PAX_FORMAT", - "DEFAULT_FORMAT", "open"] + "DEFAULT_FORMAT", "open","fully_trusted_filter", "data_filter", + "tar_filter", "FilterError", "AbsoluteLinkError", + "OutsideDestinationError", "SpecialFileError", "AbsolutePathError", + "LinkOutsideDestinationError"] + #--------------------------------------------------------- # tar constants @@ -158,6 +159,8 @@ def stn(s, length, encoding, errors): """Convert a string to a null-terminated bytes object. """ + if s is None: + raise ValueError("metadata cannot contain None") s = s.encode(encoding, errors) return s[:length] + (length - len(s)) * NUL @@ -328,15 +331,17 @@ def write(self, s): class _Stream: """Class that serves as an adapter between TarFile and a stream-like object. The stream-like object only - needs to have a read() or write() method and is accessed - blockwise. Use of gzip or bzip2 compression is possible. - A stream-like object could be for example: sys.stdin, - sys.stdout, a socket, a tape device etc. + needs to have a read() or write() method that works with bytes, + and the method is accessed blockwise. + Use of gzip or bzip2 compression is possible. + A stream-like object could be for example: sys.stdin.buffer, + sys.stdout.buffer, a socket, a tape device etc. _Stream is intended to be used only internally. """ - def __init__(self, name, mode, comptype, fileobj, bufsize): + def __init__(self, name, mode, comptype, fileobj, bufsize, + compresslevel): """Construct a _Stream object. """ self._extfileobj = True @@ -368,10 +373,10 @@ def __init__(self, name, mode, comptype, fileobj, bufsize): self.zlib = zlib self.crc = zlib.crc32(b"") if mode == "r": - self._init_read_gz() self.exception = zlib.error + self._init_read_gz() else: - self._init_write_gz() + self._init_write_gz(compresslevel) elif comptype == "bz2": try: @@ -383,7 +388,7 @@ def __init__(self, name, mode, comptype, fileobj, bufsize): self.cmp = bz2.BZ2Decompressor() self.exception = OSError else: - self.cmp = bz2.BZ2Compressor() + self.cmp = bz2.BZ2Compressor(compresslevel) elif comptype == "xz": try: @@ -410,13 +415,14 @@ def __del__(self): if hasattr(self, "closed") and not self.closed: self.close() - def _init_write_gz(self): + def _init_write_gz(self, compresslevel): """Initialize for writing with gzip compression. """ - self.cmp = self.zlib.compressobj(9, self.zlib.DEFLATED, - -self.zlib.MAX_WBITS, - self.zlib.DEF_MEM_LEVEL, - 0) + self.cmp = self.zlib.compressobj(compresslevel, + self.zlib.DEFLATED, + -self.zlib.MAX_WBITS, + self.zlib.DEF_MEM_LEVEL, + 0) timestamp = struct.pack("" % (self.__class__.__name__,self.name,id(self)) + def replace(self, *, + name=_KEEP, mtime=_KEEP, mode=_KEEP, linkname=_KEEP, + uid=_KEEP, gid=_KEEP, uname=_KEEP, gname=_KEEP, + deep=True, _KEEP=_KEEP): + """Return a deep copy of self with the given attributes replaced. + """ + if deep: + result = copy.deepcopy(self) + else: + result = copy.copy(self) + if name is not _KEEP: + result.name = name + if mtime is not _KEEP: + result.mtime = mtime + if mode is not _KEEP: + result.mode = mode + if linkname is not _KEEP: + result.linkname = linkname + if uid is not _KEEP: + result.uid = uid + if gid is not _KEEP: + result.gid = gid + if uname is not _KEEP: + result.uname = uname + if gname is not _KEEP: + result.gname = gname + return result + def get_info(self): """Return the TarInfo's attributes as a dictionary. """ + if self.mode is None: + mode = None + else: + mode = self.mode & 0o7777 info = { "name": self.name, - "mode": self.mode & 0o7777, + "mode": mode, "uid": self.uid, "gid": self.gid, "size": self.size, @@ -820,6 +986,9 @@ def tobuf(self, format=DEFAULT_FORMAT, encoding=ENCODING, errors="surrogateescap """Return a tar header as a string of 512 byte blocks. """ info = self.get_info() + for name, value in info.items(): + if value is None: + raise ValueError("%s may not be None" % name) if format == USTAR_FORMAT: return self.create_ustar_header(info, encoding, errors) @@ -950,6 +1119,12 @@ def _create_header(info, format, encoding, errors): devmajor = stn("", 8, encoding, errors) devminor = stn("", 8, encoding, errors) + # None values in metadata should cause ValueError. + # itn()/stn() do this for all fields except type. + filetype = info.get("type", REGTYPE) + if filetype is None: + raise ValueError("TarInfo.type must not be None") + parts = [ stn(info.get("name", ""), 100, encoding, errors), itn(info.get("mode", 0) & 0o7777, 8, format), @@ -958,7 +1133,7 @@ def _create_header(info, format, encoding, errors): itn(info.get("size", 0), 12, format), itn(info.get("mtime", 0), 12, format), b" ", # checksum field - info.get("type", REGTYPE), + filetype, stn(info.get("linkname", ""), 100, encoding, errors), info.get("magic", POSIX_MAGIC), stn(info.get("uname", ""), 32, encoding, errors), @@ -998,7 +1173,7 @@ def _create_gnu_long_header(cls, name, type, encoding, errors): # create extended header + name blocks. return cls._create_header(info, USTAR_FORMAT, encoding, errors) + \ - cls._create_payload(name) + cls._create_payload(name) @classmethod def _create_pax_generic_header(cls, pax_headers, type, encoding): @@ -1049,7 +1224,7 @@ def _create_pax_generic_header(cls, pax_headers, type, encoding): # Create pax header + record blocks. return cls._create_header(info, USTAR_FORMAT, "ascii", "replace") + \ - cls._create_payload(records) + cls._create_payload(records) @classmethod def frombuf(cls, buf, encoding, errors): @@ -1240,41 +1415,59 @@ def _proc_pax(self, tarfile): else: pax_headers = tarfile.pax_headers.copy() - # Check if the pax header contains a hdrcharset field. This tells us - # the encoding of the path, linkpath, uname and gname fields. Normally, - # these fields are UTF-8 encoded but since POSIX.1-2008 tar - # implementations are allowed to store them as raw binary strings if - # the translation to UTF-8 fails. - match = re.search(br"\d+ hdrcharset=([^\n]+)\n", buf) - if match is not None: - pax_headers["hdrcharset"] = match.group(1).decode("utf-8") - - # For the time being, we don't care about anything other than "BINARY". - # The only other value that is currently allowed by the standard is - # "ISO-IR 10646 2000 UTF-8" in other words UTF-8. - hdrcharset = pax_headers.get("hdrcharset") - if hdrcharset == "BINARY": - encoding = tarfile.encoding - else: - encoding = "utf-8" - # Parse pax header information. A record looks like that: # "%d %s=%s\n" % (length, keyword, value). length is the size # of the complete record including the length field itself and - # the newline. keyword and value are both UTF-8 encoded strings. - regex = re.compile(br"(\d+) ([^=]+)=") + # the newline. pos = 0 - while True: - match = regex.match(buf, pos) - if not match: - break + encoding = None + raw_headers = [] + while len(buf) > pos and buf[pos] != 0x00: + if not (match := _header_length_prefix_re.match(buf, pos)): + raise InvalidHeaderError("invalid header") + try: + length = int(match.group(1)) + except ValueError: + raise InvalidHeaderError("invalid header") + # Headers must be at least 5 bytes, shortest being '5 x=\n'. + # Value is allowed to be empty. + if length < 5: + raise InvalidHeaderError("invalid header") + if pos + length > len(buf): + raise InvalidHeaderError("invalid header") - length, keyword = match.groups() - length = int(length) - if length == 0: + header_value_end_offset = match.start(1) + length - 1 # Last byte of the header + keyword_and_value = buf[match.end(1) + 1:header_value_end_offset] + raw_keyword, equals, raw_value = keyword_and_value.partition(b"=") + + # Check the framing of the header. The last character must be '\n' (0x0A) + if not raw_keyword or equals != b"=" or buf[header_value_end_offset] != 0x0A: raise InvalidHeaderError("invalid header") - value = buf[match.end(2) + 1:match.start(1) + length - 1] + raw_headers.append((length, raw_keyword, raw_value)) + + # Check if the pax header contains a hdrcharset field. This tells us + # the encoding of the path, linkpath, uname and gname fields. Normally, + # these fields are UTF-8 encoded but since POSIX.1-2008 tar + # implementations are allowed to store them as raw binary strings if + # the translation to UTF-8 fails. For the time being, we don't care about + # anything other than "BINARY". The only other value that is currently + # allowed by the standard is "ISO-IR 10646 2000 UTF-8" in other words UTF-8. + # Note that we only follow the initial 'hdrcharset' setting to preserve + # the initial behavior of the 'tarfile' module. + if raw_keyword == b"hdrcharset" and encoding is None: + if raw_value == b"BINARY": + encoding = tarfile.encoding + else: # This branch ensures only the first 'hdrcharset' header is used. + encoding = "utf-8" + + pos += length + # If no explicit hdrcharset is set, we use UTF-8 as a default. + if encoding is None: + encoding = "utf-8" + + # After parsing the raw headers we can decode them to text. + for length, raw_keyword, raw_value in raw_headers: # Normally, we could just use "utf-8" as the encoding and "strict" # as the error handler, but we better not take the risk. For # example, GNU tar <= 1.23 is known to store filenames it cannot @@ -1282,17 +1475,16 @@ def _proc_pax(self, tarfile): # hdrcharset=BINARY header). # We first try the strict standard encoding, and if that fails we # fall back on the user's encoding and error handler. - keyword = self._decode_pax_field(keyword, "utf-8", "utf-8", - tarfile.errors) + keyword = self._decode_pax_field(raw_keyword, "utf-8", "utf-8", + tarfile.errors) if keyword in PAX_NAME_FIELDS: - value = self._decode_pax_field(value, encoding, tarfile.encoding, - tarfile.errors) + value = self._decode_pax_field(raw_value, encoding, tarfile.encoding, + tarfile.errors) else: - value = self._decode_pax_field(value, "utf-8", "utf-8", - tarfile.errors) + value = self._decode_pax_field(raw_value, "utf-8", "utf-8", + tarfile.errors) pax_headers[keyword] = value - pos += length # Fetch the next header. try: @@ -1307,7 +1499,7 @@ def _proc_pax(self, tarfile): elif "GNU.sparse.size" in pax_headers: # GNU extended sparse format version 0.0. - self._proc_gnusparse_00(next, pax_headers, buf) + self._proc_gnusparse_00(next, raw_headers) elif pax_headers.get("GNU.sparse.major") == "1" and pax_headers.get("GNU.sparse.minor") == "0": # GNU extended sparse format version 1.0. @@ -1329,15 +1521,24 @@ def _proc_pax(self, tarfile): return next - def _proc_gnusparse_00(self, next, pax_headers, buf): + def _proc_gnusparse_00(self, next, raw_headers): """Process a GNU tar extended sparse header, version 0.0. """ offsets = [] - for match in re.finditer(br"\d+ GNU.sparse.offset=(\d+)\n", buf): - offsets.append(int(match.group(1))) numbytes = [] - for match in re.finditer(br"\d+ GNU.sparse.numbytes=(\d+)\n", buf): - numbytes.append(int(match.group(1))) + for _, keyword, value in raw_headers: + if keyword == b"GNU.sparse.offset": + try: + offsets.append(int(value.decode())) + except ValueError: + raise InvalidHeaderError("invalid header") + + elif keyword == b"GNU.sparse.numbytes": + try: + numbytes.append(int(value.decode())) + except ValueError: + raise InvalidHeaderError("invalid header") + next.sparse = list(zip(offsets, numbytes)) def _proc_gnusparse_01(self, next, pax_headers): @@ -1449,14 +1650,14 @@ class TarFile(object): debug = 0 # May be set from 0 (no msgs) to 3 (all msgs) dereference = False # If true, add content of linked file to the - # tar file, else the link. + # tar file, else the link. ignore_zeros = False # If true, skips empty or invalid blocks and - # continues processing. + # continues processing. errorlevel = 1 # If 0, fatal errors only appear in debug - # messages (if debug >= 0). If > 0, errors - # are passed to the caller as exceptions. + # messages (if debug >= 0). If > 0, errors + # are passed to the caller as exceptions. format = DEFAULT_FORMAT # The format to use when creating an archive. @@ -1468,10 +1669,12 @@ class TarFile(object): fileobject = ExFileObject # The file-object for extractfile(). + extraction_filter = None # The default filter for extraction. + def __init__(self, name=None, mode="r", fileobj=None, format=None, - tarinfo=None, dereference=None, ignore_zeros=None, encoding=None, - errors="surrogateescape", pax_headers=None, debug=None, - errorlevel=None, copybufsize=None): + tarinfo=None, dereference=None, ignore_zeros=None, encoding=None, + errors="surrogateescape", pax_headers=None, debug=None, + errorlevel=None, copybufsize=None): """Open an (uncompressed) tar archive `name'. `mode' is either 'r' to read from an existing archive, 'a' to append data to an existing file or 'w' to create a new file overwriting an existing one. `mode' @@ -1495,7 +1698,7 @@ def __init__(self, name=None, mode="r", fileobj=None, format=None, self._extfileobj = False else: if (name is None and hasattr(fileobj, "name") and - isinstance(fileobj.name, (str, bytes))): + isinstance(fileobj.name, (str, bytes))): name = fileobj.name if hasattr(fileobj, "mode"): self._mode = fileobj.mode @@ -1532,9 +1735,9 @@ def __init__(self, name=None, mode="r", fileobj=None, format=None, self.members = [] # list of members as TarInfo objects self._loaded = False # flag if all members have been read self.offset = self.fileobj.tell() - # current position in the archive file + # current position in the archive file self.inodes = {} # dictionary caching the inodes of - # archive members already added + # archive members already added try: if self.mode == "r": @@ -1659,7 +1862,9 @@ def not_compressed(comptype): if filemode not in ("r", "w"): raise ValueError("mode must be 'r' or 'w'") - stream = _Stream(name, filemode, comptype, fileobj, bufsize) + compresslevel = kwargs.pop("compresslevel", 9) + stream = _Stream(name, filemode, comptype, fileobj, bufsize, + compresslevel) try: t = cls(name, filemode, stream, **kwargs) except: @@ -1820,7 +2025,7 @@ def getmembers(self): self._check() if not self._loaded: # if we want to obtain a list of self._load() # all members, we first have to - # scan the whole archive. + # scan the whole archive. return self.members def getnames(self): @@ -1940,16 +2145,22 @@ def list(self, verbose=True, *, members=None): members = self for tarinfo in members: if verbose: - _safe_print(stat.filemode(tarinfo.mode)) + if tarinfo.mode is None: + _safe_print("??????????") + else: + _safe_print(stat.filemode(tarinfo.mode)) _safe_print("%s/%s" % (tarinfo.uname or tarinfo.uid, tarinfo.gname or tarinfo.gid)) if tarinfo.ischr() or tarinfo.isblk(): _safe_print("%10s" % - ("%d,%d" % (tarinfo.devmajor, tarinfo.devminor))) + ("%d,%d" % (tarinfo.devmajor, tarinfo.devminor))) else: _safe_print("%10d" % tarinfo.size) - _safe_print("%d-%02d-%02d %02d:%02d:%02d" \ - % time.localtime(tarinfo.mtime)[:6]) + if tarinfo.mtime is None: + _safe_print("????-??-?? ??:??:??") + else: + _safe_print("%d-%02d-%02d %02d:%02d:%02d" \ + % time.localtime(tarinfo.mtime)[:6]) _safe_print(tarinfo.name + ("/" if tarinfo.isdir() else "")) @@ -2006,7 +2217,7 @@ def add(self, name, arcname=None, recursive=True, *, filter=None): if recursive: for f in sorted(os.listdir(name)): self.add(os.path.join(name, f), os.path.join(arcname, f), - recursive, filter=filter) + recursive, filter=filter) else: self.addfile(tarinfo) @@ -2036,32 +2247,63 @@ def addfile(self, tarinfo, fileobj=None): self.members.append(tarinfo) - def extractall(self, path=".", members=None, *, numeric_owner=False): + def _get_filter_function(self, filter): + if filter is None: + filter = self.extraction_filter + if filter is None: + warnings.warn( + 'Python 3.14 will, by default, filter extracted tar ' + + 'archives and reject files or modify their metadata. ' + + 'Use the filter argument to control this behavior.', + DeprecationWarning, stacklevel=3) + return fully_trusted_filter + if isinstance(filter, str): + raise TypeError( + 'String names are not supported for ' + + 'TarFile.extraction_filter. Use a function such as ' + + 'tarfile.data_filter directly.') + return filter + if callable(filter): + return filter + try: + return _NAMED_FILTERS[filter] + except KeyError: + raise ValueError(f"filter {filter!r} not found") from None + + def extractall(self, path=".", members=None, *, numeric_owner=False, + filter=None): """Extract all members from the archive to the current working directory and set owner, modification time and permissions on directories afterwards. `path' specifies a different directory to extract to. `members' is optional and must be a subset of the list returned by getmembers(). If `numeric_owner` is True, only the numbers for user/group names are used and not the names. + + The `filter` function will be called on each member just + before extraction. + It can return a changed TarInfo or None to skip the member. + String names of common filters are accepted. """ directories = [] + filter_function = self._get_filter_function(filter) if members is None: members = self - for tarinfo in members: + for member in members: + tarinfo = self._get_extract_tarinfo(member, filter_function, path) + if tarinfo is None: + continue if tarinfo.isdir(): - # Extract directories with a safe mode. + # For directories, delay setting attributes until later, + # since permissions can interfere with extraction and + # extracting contents can reset mtime. directories.append(tarinfo) - tarinfo = copy.copy(tarinfo) - tarinfo.mode = 0o700 - # Do not set_attrs directories, as we will do that further down - self.extract(tarinfo, path, set_attrs=not tarinfo.isdir(), - numeric_owner=numeric_owner) + self._extract_one(tarinfo, path, set_attrs=not tarinfo.isdir(), + numeric_owner=numeric_owner) # Reverse sort directories. - directories.sort(key=lambda a: a.name) - directories.reverse() + directories.sort(key=lambda a: a.name, reverse=True) # Set correct owner, mtime and filemode on directories. for tarinfo in directories: @@ -2071,12 +2313,10 @@ def extractall(self, path=".", members=None, *, numeric_owner=False): self.utime(tarinfo, dirpath) self.chmod(tarinfo, dirpath) except ExtractError as e: - if self.errorlevel > 1: - raise - else: - self._dbg(1, "tarfile: %s" % e) + self._handle_nonfatal_error(e) - def extract(self, member, path="", set_attrs=True, *, numeric_owner=False): + def extract(self, member, path="", set_attrs=True, *, numeric_owner=False, + filter=None): """Extract a member from the archive to the current working directory, using its full name. Its file information is extracted as accurately as possible. `member' may be a filename or a TarInfo object. You can @@ -2084,35 +2324,70 @@ def extract(self, member, path="", set_attrs=True, *, numeric_owner=False): mtime, mode) are set unless `set_attrs' is False. If `numeric_owner` is True, only the numbers for user/group names are used and not the names. + + The `filter` function will be called before extraction. + It can return a changed TarInfo or None to skip the member. + String names of common filters are accepted. """ - self._check("r") + filter_function = self._get_filter_function(filter) + tarinfo = self._get_extract_tarinfo(member, filter_function, path) + if tarinfo is not None: + self._extract_one(tarinfo, path, set_attrs, numeric_owner) + def _get_extract_tarinfo(self, member, filter_function, path): + """Get filtered TarInfo (or None) from member, which might be a str""" if isinstance(member, str): tarinfo = self.getmember(member) else: tarinfo = member + unfiltered = tarinfo + try: + tarinfo = filter_function(tarinfo, path) + except (OSError, FilterError) as e: + self._handle_fatal_error(e) + except ExtractError as e: + self._handle_nonfatal_error(e) + if tarinfo is None: + self._dbg(2, "tarfile: Excluded %r" % unfiltered.name) + return None # Prepare the link target for makelink(). if tarinfo.islnk(): + tarinfo = copy.copy(tarinfo) tarinfo._link_target = os.path.join(path, tarinfo.linkname) + return tarinfo + + def _extract_one(self, tarinfo, path, set_attrs, numeric_owner): + """Extract from filtered tarinfo to disk""" + self._check("r") try: self._extract_member(tarinfo, os.path.join(path, tarinfo.name), set_attrs=set_attrs, numeric_owner=numeric_owner) except OSError as e: - if self.errorlevel > 0: - raise - else: - if e.filename is None: - self._dbg(1, "tarfile: %s" % e.strerror) - else: - self._dbg(1, "tarfile: %s %r" % (e.strerror, e.filename)) + self._handle_fatal_error(e) except ExtractError as e: - if self.errorlevel > 1: - raise + self._handle_nonfatal_error(e) + + def _handle_nonfatal_error(self, e): + """Handle non-fatal error (ExtractError) according to errorlevel""" + if self.errorlevel > 1: + raise + else: + self._dbg(1, "tarfile: %s" % e) + + def _handle_fatal_error(self, e): + """Handle "fatal" error according to self.errorlevel""" + if self.errorlevel > 0: + raise + elif isinstance(e, OSError): + if e.filename is None: + self._dbg(1, "tarfile: %s" % e.strerror) else: - self._dbg(1, "tarfile: %s" % e) + self._dbg(1, "tarfile: %s %r" % (e.strerror, e.filename)) + else: + self._dbg(1, "tarfile: %s %s" % (type(e).__name__, e)) def extractfile(self, member): """Extract a member from the archive as a file object. `member' may be @@ -2199,11 +2474,16 @@ def makedir(self, tarinfo, targetpath): """Make a directory called targetpath. """ try: - # Use a safe mode for the directory, the real mode is set - # later in _extract_member(). - os.mkdir(targetpath, 0o700) + if tarinfo.mode is None: + # Use the system's default mode + os.mkdir(targetpath) + else: + # Use a safe mode for the directory, the real mode is set + # later in _extract_member(). + os.mkdir(targetpath, 0o700) except FileExistsError: - pass + if not os.path.isdir(targetpath): + raise def makefile(self, tarinfo, targetpath): """Make a file called targetpath. @@ -2244,6 +2524,9 @@ def makedev(self, tarinfo, targetpath): raise ExtractError("special devices not supported by system") mode = tarinfo.mode + if mode is None: + # Use mknod's default + mode = 0o600 if tarinfo.isblk(): mode |= stat.S_IFBLK else: @@ -2265,7 +2548,6 @@ def makelink(self, tarinfo, targetpath): os.unlink(targetpath) os.symlink(tarinfo.linkname, targetpath) else: - # See extract(). if os.path.exists(tarinfo._link_target): os.link(tarinfo._link_target, targetpath) else: @@ -2290,15 +2572,19 @@ def chown(self, tarinfo, targetpath, numeric_owner): u = tarinfo.uid if not numeric_owner: try: - if grp: + if grp and tarinfo.gname: g = grp.getgrnam(tarinfo.gname)[2] except KeyError: pass try: - if pwd: + if pwd and tarinfo.uname: u = pwd.getpwnam(tarinfo.uname)[2] except KeyError: pass + if g is None: + g = -1 + if u is None: + u = -1 try: if tarinfo.issym() and hasattr(os, "lchown"): os.lchown(targetpath, u, g) @@ -2310,6 +2596,8 @@ def chown(self, tarinfo, targetpath, numeric_owner): def chmod(self, tarinfo, targetpath): """Set file permissions of targetpath according to tarinfo. """ + if tarinfo.mode is None: + return try: os.chmod(targetpath, tarinfo.mode) except OSError as e: @@ -2318,10 +2606,13 @@ def chmod(self, tarinfo, targetpath): def utime(self, tarinfo, targetpath): """Set modification time of targetpath according to tarinfo. """ + mtime = tarinfo.mtime + if mtime is None: + return if not hasattr(os, 'utime'): return try: - os.utime(targetpath, (tarinfo.mtime, tarinfo.mtime)) + os.utime(targetpath, (mtime, mtime)) except OSError as e: raise ExtractError("could not change modification time") from e @@ -2339,6 +2630,8 @@ def next(self): # Advance the file pointer. if self.offset != self.fileobj.tell(): + if self.offset == 0: + return None self.fileobj.seek(self.offset - 1) if not self.fileobj.read(1): raise ReadError("unexpected end of data") @@ -2397,13 +2690,26 @@ def _getmember(self, name, tarinfo=None, normalize=False): members = self.getmembers() # Limit the member search list up to tarinfo. + skipping = False if tarinfo is not None: - members = members[:members.index(tarinfo)] + try: + index = members.index(tarinfo) + except ValueError: + # The given starting point might be a (modified) copy. + # We'll later skip members until we find an equivalent. + skipping = True + else: + # Happy fast path + members = members[:index] if normalize: name = os.path.normpath(name) for member in reversed(members): + if skipping: + if tarinfo.offset == member.offset: + skipping = False + continue if normalize: member_name = os.path.normpath(member.name) else: @@ -2412,14 +2718,16 @@ def _getmember(self, name, tarinfo=None, normalize=False): if name == member_name: return member + if skipping: + # Starting point was not found + raise ValueError(tarinfo) + def _load(self): """Read through the entire archive file and look for readable members. """ - while True: - tarinfo = self.next() - if tarinfo is None: - break + while self.next() is not None: + pass self._loaded = True def _check(self, mode=None): @@ -2504,6 +2812,7 @@ def __exit__(self, type, value, traceback): #-------------------- # exported functions #-------------------- + def is_tarfile(name): """Return True if name points to a tar archive that we are able to handle, else return False. @@ -2512,7 +2821,9 @@ def is_tarfile(name): """ try: if hasattr(name, "read"): + pos = name.tell() t = open(fileobj=name) + name.seek(pos) else: t = open(name) t.close() @@ -2530,6 +2841,10 @@ def main(): parser = argparse.ArgumentParser(description=description) parser.add_argument('-v', '--verbose', action='store_true', default=False, help='Verbose output') + parser.add_argument('--filter', metavar='', + choices=_NAMED_FILTERS, + help='Filter for extraction') + group = parser.add_mutually_exclusive_group(required=True) group.add_argument('-l', '--list', metavar='', help='Show listing of a tarfile') @@ -2541,8 +2856,12 @@ def main(): help='Create tarfile from sources') group.add_argument('-t', '--test', metavar='', help='Test if a tarfile is valid') + args = parser.parse_args() + if args.filter and args.extract is None: + parser.exit(1, '--filter is only valid for extraction\n') + if args.test is not None: src = args.test if is_tarfile(src): @@ -2573,7 +2892,7 @@ def main(): if is_tarfile(src): with TarFile.open(src, 'r:*') as tf: - tf.extractall(path=curdir) + tf.extractall(path=curdir, filter=args.filter) if args.verbose: if curdir == '.': msg = '{!r} file is extracted.'.format(src) diff --git a/Lib/test/archiver_tests.py b/Lib/test/archiver_tests.py new file mode 100644 index 0000000000..1a4bbb9e57 --- /dev/null +++ b/Lib/test/archiver_tests.py @@ -0,0 +1,155 @@ +"""Tests common to tarfile and zipfile.""" + +import os +import sys + +from test.support import os_helper + +class OverwriteTests: + + def setUp(self): + os.makedirs(self.testdir) + self.addCleanup(os_helper.rmtree, self.testdir) + + def create_file(self, path, content=b''): + with open(path, 'wb') as f: + f.write(content) + + def open(self, path): + raise NotImplementedError + + def extractall(self, ar): + raise NotImplementedError + + + def test_overwrite_file_as_file(self): + target = os.path.join(self.testdir, 'test') + self.create_file(target, b'content') + with self.open(self.ar_with_file) as ar: + self.extractall(ar) + self.assertTrue(os.path.isfile(target)) + with open(target, 'rb') as f: + self.assertEqual(f.read(), b'newcontent') + + def test_overwrite_dir_as_dir(self): + target = os.path.join(self.testdir, 'test') + os.mkdir(target) + with self.open(self.ar_with_dir) as ar: + self.extractall(ar) + self.assertTrue(os.path.isdir(target)) + + def test_overwrite_dir_as_implicit_dir(self): + target = os.path.join(self.testdir, 'test') + os.mkdir(target) + with self.open(self.ar_with_implicit_dir) as ar: + self.extractall(ar) + self.assertTrue(os.path.isdir(target)) + self.assertTrue(os.path.isfile(os.path.join(target, 'file'))) + with open(os.path.join(target, 'file'), 'rb') as f: + self.assertEqual(f.read(), b'newcontent') + + def test_overwrite_dir_as_file(self): + target = os.path.join(self.testdir, 'test') + os.mkdir(target) + with self.open(self.ar_with_file) as ar: + with self.assertRaises(PermissionError if sys.platform == 'win32' + else IsADirectoryError): + self.extractall(ar) + self.assertTrue(os.path.isdir(target)) + + def test_overwrite_file_as_dir(self): + target = os.path.join(self.testdir, 'test') + self.create_file(target, b'content') + with self.open(self.ar_with_dir) as ar: + with self.assertRaises(FileExistsError): + self.extractall(ar) + self.assertTrue(os.path.isfile(target)) + with open(target, 'rb') as f: + self.assertEqual(f.read(), b'content') + + def test_overwrite_file_as_implicit_dir(self): + target = os.path.join(self.testdir, 'test') + self.create_file(target, b'content') + with self.open(self.ar_with_implicit_dir) as ar: + with self.assertRaises(FileNotFoundError if sys.platform == 'win32' + else NotADirectoryError): + self.extractall(ar) + self.assertTrue(os.path.isfile(target)) + with open(target, 'rb') as f: + self.assertEqual(f.read(), b'content') + + @os_helper.skip_unless_symlink + def test_overwrite_file_symlink_as_file(self): + # XXX: It is potential security vulnerability. + target = os.path.join(self.testdir, 'test') + target2 = os.path.join(self.testdir, 'test2') + self.create_file(target2, b'content') + os.symlink('test2', target) + with self.open(self.ar_with_file) as ar: + self.extractall(ar) + self.assertTrue(os.path.islink(target)) + self.assertTrue(os.path.isfile(target2)) + with open(target2, 'rb') as f: + self.assertEqual(f.read(), b'newcontent') + + @os_helper.skip_unless_symlink + def test_overwrite_broken_file_symlink_as_file(self): + # XXX: It is potential security vulnerability. + target = os.path.join(self.testdir, 'test') + target2 = os.path.join(self.testdir, 'test2') + os.symlink('test2', target) + with self.open(self.ar_with_file) as ar: + self.extractall(ar) + self.assertTrue(os.path.islink(target)) + self.assertTrue(os.path.isfile(target2)) + with open(target2, 'rb') as f: + self.assertEqual(f.read(), b'newcontent') + + @os_helper.skip_unless_symlink + def test_overwrite_dir_symlink_as_dir(self): + # XXX: It is potential security vulnerability. + target = os.path.join(self.testdir, 'test') + target2 = os.path.join(self.testdir, 'test2') + os.mkdir(target2) + os.symlink('test2', target, target_is_directory=True) + with self.open(self.ar_with_dir) as ar: + self.extractall(ar) + self.assertTrue(os.path.islink(target)) + self.assertTrue(os.path.isdir(target2)) + + @os_helper.skip_unless_symlink + def test_overwrite_dir_symlink_as_implicit_dir(self): + # XXX: It is potential security vulnerability. + target = os.path.join(self.testdir, 'test') + target2 = os.path.join(self.testdir, 'test2') + os.mkdir(target2) + os.symlink('test2', target, target_is_directory=True) + with self.open(self.ar_with_implicit_dir) as ar: + self.extractall(ar) + self.assertTrue(os.path.islink(target)) + self.assertTrue(os.path.isdir(target2)) + self.assertTrue(os.path.isfile(os.path.join(target2, 'file'))) + with open(os.path.join(target2, 'file'), 'rb') as f: + self.assertEqual(f.read(), b'newcontent') + + @os_helper.skip_unless_symlink + def test_overwrite_broken_dir_symlink_as_dir(self): + target = os.path.join(self.testdir, 'test') + target2 = os.path.join(self.testdir, 'test2') + os.symlink('test2', target, target_is_directory=True) + with self.open(self.ar_with_dir) as ar: + with self.assertRaises(FileExistsError): + self.extractall(ar) + self.assertTrue(os.path.islink(target)) + self.assertFalse(os.path.exists(target2)) + + @os_helper.skip_unless_symlink + def test_overwrite_broken_dir_symlink_as_implicit_dir(self): + target = os.path.join(self.testdir, 'test') + target2 = os.path.join(self.testdir, 'test2') + os.symlink('test2', target, target_is_directory=True) + with self.open(self.ar_with_implicit_dir) as ar: + with self.assertRaises(FileExistsError): + self.extractall(ar) + self.assertTrue(os.path.islink(target)) + self.assertFalse(os.path.exists(target2)) diff --git a/Lib/test/test_docxmlrpc.py b/Lib/test/test_docxmlrpc.py index 99469a5849..56e3b6895d 100644 --- a/Lib/test/test_docxmlrpc.py +++ b/Lib/test/test_docxmlrpc.py @@ -88,8 +88,6 @@ def tearDown(self): self.thread.join() self.serv.server_close() - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_valid_get_response(self): self.client.request("GET", "/") response = self.client.getresponse() @@ -135,8 +133,6 @@ def test_lambda(self): b'<lambda>(x, y)'), response.read()) - # TODO: RUSTPYTHON - @unittest.expectedFailure @make_request_and_skipIf(sys.flags.optimize >= 2, "Docstrings are omitted with -O2 and above") def test_autolinking(self): diff --git a/Lib/test/test_gzip.py b/Lib/test/test_gzip.py index 6a709d3f66..36989f5d59 100644 --- a/Lib/test/test_gzip.py +++ b/Lib/test/test_gzip.py @@ -5,7 +5,6 @@ import functools import io import os -import pathlib import struct import sys import unittest @@ -16,6 +15,7 @@ from test.support.script_helper import assert_python_ok, assert_python_failure gzip = import_helper.import_module('gzip') +zlib = import_helper.import_module('zlib') data1 = b""" int length=DEFAULTALLOC, err = Z_OK; PyObject *RetVal; @@ -78,16 +78,18 @@ def test_write(self): f.close() def test_write_read_with_pathlike_file(self): - filename = pathlib.Path(self.filename) + filename = os_helper.FakePath(self.filename) with gzip.GzipFile(filename, 'w') as f: f.write(data1 * 50) self.assertIsInstance(f.name, str) + self.assertEqual(f.name, self.filename) with gzip.GzipFile(filename, 'a') as f: f.write(data1) with gzip.GzipFile(filename) as f: d = f.read() self.assertEqual(d, data1 * 51) self.assertIsInstance(f.name, str) + self.assertEqual(f.name, self.filename) # The following test_write_xy methods test that write accepts # the corresponding bytes-like object type as input @@ -247,6 +249,8 @@ def test_readlines(self): L = f.readlines(150) if L == []: break + # TODO: RUSTPYTHON + @unittest.expectedFailure def test_seek_read(self): self.test_write() # Try seek, read test @@ -441,6 +445,8 @@ def test_non_seekable_file(self): with gzip.GzipFile(fileobj=buf, mode="rb") as f: self.assertEqual(f.read(), uncompressed) + # TODO: RUSTPYTHON + @unittest.expectedFailure def test_peek(self): uncompressed = data1 * 200 with gzip.GzipFile(self.filename, "wb") as f: @@ -471,13 +477,118 @@ def test_textio_readlines(self): with io.TextIOWrapper(f, encoding="ascii") as t: self.assertEqual(t.readlines(), lines) + def test_fileobj_with_name(self): + with open(self.filename, "xb") as raw: + with gzip.GzipFile(fileobj=raw, mode="x") as f: + f.write(b'one') + self.assertEqual(f.name, raw.name) + self.assertEqual(f.fileno(), raw.fileno()) + self.assertEqual(f.mode, gzip.WRITE) + self.assertIs(f.readable(), False) + self.assertIs(f.writable(), True) + self.assertIs(f.seekable(), True) + self.assertIs(f.closed, False) + self.assertIs(f.closed, True) + self.assertEqual(f.name, raw.name) + self.assertRaises(AttributeError, f.fileno) + self.assertEqual(f.mode, gzip.WRITE) + self.assertIs(f.readable(), False) + self.assertIs(f.writable(), True) + self.assertIs(f.seekable(), True) + + with open(self.filename, "wb") as raw: + with gzip.GzipFile(fileobj=raw, mode="w") as f: + f.write(b'two') + self.assertEqual(f.name, raw.name) + self.assertEqual(f.fileno(), raw.fileno()) + self.assertEqual(f.mode, gzip.WRITE) + self.assertIs(f.readable(), False) + self.assertIs(f.writable(), True) + self.assertIs(f.seekable(), True) + self.assertIs(f.closed, False) + self.assertIs(f.closed, True) + self.assertEqual(f.name, raw.name) + self.assertRaises(AttributeError, f.fileno) + self.assertEqual(f.mode, gzip.WRITE) + self.assertIs(f.readable(), False) + self.assertIs(f.writable(), True) + self.assertIs(f.seekable(), True) + + with open(self.filename, "ab") as raw: + with gzip.GzipFile(fileobj=raw, mode="a") as f: + f.write(b'three') + self.assertEqual(f.name, raw.name) + self.assertEqual(f.fileno(), raw.fileno()) + self.assertEqual(f.mode, gzip.WRITE) + self.assertIs(f.readable(), False) + self.assertIs(f.writable(), True) + self.assertIs(f.seekable(), True) + self.assertIs(f.closed, False) + self.assertIs(f.closed, True) + self.assertEqual(f.name, raw.name) + self.assertRaises(AttributeError, f.fileno) + self.assertEqual(f.mode, gzip.WRITE) + self.assertIs(f.readable(), False) + self.assertIs(f.writable(), True) + self.assertIs(f.seekable(), True) + + with open(self.filename, "rb") as raw: + with gzip.GzipFile(fileobj=raw, mode="r") as f: + self.assertEqual(f.read(), b'twothree') + self.assertEqual(f.name, raw.name) + self.assertEqual(f.fileno(), raw.fileno()) + self.assertEqual(f.mode, gzip.READ) + self.assertIs(f.readable(), True) + self.assertIs(f.writable(), False) + self.assertIs(f.seekable(), True) + self.assertIs(f.closed, False) + self.assertIs(f.closed, True) + self.assertEqual(f.name, raw.name) + self.assertRaises(AttributeError, f.fileno) + self.assertEqual(f.mode, gzip.READ) + self.assertIs(f.readable(), True) + self.assertIs(f.writable(), False) + self.assertIs(f.seekable(), True) + def test_fileobj_from_fdopen(self): # Issue #13781: Opening a GzipFile for writing fails when using a # fileobj created with os.fdopen(). - fd = os.open(self.filename, os.O_WRONLY | os.O_CREAT) - with os.fdopen(fd, "wb") as f: - with gzip.GzipFile(fileobj=f, mode="w") as g: - pass + fd = os.open(self.filename, os.O_WRONLY | os.O_CREAT | os.O_EXCL) + with os.fdopen(fd, "xb") as raw: + with gzip.GzipFile(fileobj=raw, mode="x") as f: + f.write(b'one') + self.assertEqual(f.name, '') + self.assertEqual(f.fileno(), raw.fileno()) + self.assertIs(f.closed, True) + self.assertEqual(f.name, '') + self.assertRaises(AttributeError, f.fileno) + + fd = os.open(self.filename, os.O_WRONLY | os.O_CREAT | os.O_TRUNC) + with os.fdopen(fd, "wb") as raw: + with gzip.GzipFile(fileobj=raw, mode="w") as f: + f.write(b'two') + self.assertEqual(f.name, '') + self.assertEqual(f.fileno(), raw.fileno()) + self.assertEqual(f.name, '') + self.assertRaises(AttributeError, f.fileno) + + fd = os.open(self.filename, os.O_WRONLY | os.O_CREAT | os.O_APPEND) + with os.fdopen(fd, "ab") as raw: + with gzip.GzipFile(fileobj=raw, mode="a") as f: + f.write(b'three') + self.assertEqual(f.name, '') + self.assertEqual(f.fileno(), raw.fileno()) + self.assertEqual(f.name, '') + self.assertRaises(AttributeError, f.fileno) + + fd = os.open(self.filename, os.O_RDONLY) + with os.fdopen(fd, "rb") as raw: + with gzip.GzipFile(fileobj=raw, mode="r") as f: + self.assertEqual(f.read(), b'twothree') + self.assertEqual(f.name, '') + self.assertEqual(f.fileno(), raw.fileno()) + self.assertEqual(f.name, '') + self.assertRaises(AttributeError, f.fileno) def test_fileobj_mode(self): gzip.GzipFile(self.filename, "wb").close() @@ -507,17 +618,69 @@ def test_fileobj_mode(self): def test_bytes_filename(self): str_filename = self.filename - try: - bytes_filename = str_filename.encode("ascii") - except UnicodeEncodeError: - self.skipTest("Temporary file name needs to be ASCII") + bytes_filename = os.fsencode(str_filename) with gzip.GzipFile(bytes_filename, "wb") as f: f.write(data1 * 50) + self.assertEqual(f.name, bytes_filename) with gzip.GzipFile(bytes_filename, "rb") as f: self.assertEqual(f.read(), data1 * 50) + self.assertEqual(f.name, bytes_filename) # Sanity check that we are actually operating on the right file. with gzip.GzipFile(str_filename, "rb") as f: self.assertEqual(f.read(), data1 * 50) + self.assertEqual(f.name, str_filename) + + def test_fileobj_without_name(self): + bio = io.BytesIO() + with gzip.GzipFile(fileobj=bio, mode='wb') as f: + f.write(data1 * 50) + self.assertEqual(f.name, '') + self.assertRaises(io.UnsupportedOperation, f.fileno) + self.assertEqual(f.mode, gzip.WRITE) + self.assertIs(f.readable(), False) + self.assertIs(f.writable(), True) + self.assertIs(f.seekable(), True) + self.assertIs(f.closed, False) + self.assertIs(f.closed, True) + self.assertEqual(f.name, '') + self.assertRaises(AttributeError, f.fileno) + self.assertEqual(f.mode, gzip.WRITE) + self.assertIs(f.readable(), False) + self.assertIs(f.writable(), True) + self.assertIs(f.seekable(), True) + + bio.seek(0) + with gzip.GzipFile(fileobj=bio, mode='rb') as f: + self.assertEqual(f.read(), data1 * 50) + self.assertEqual(f.name, '') + self.assertRaises(io.UnsupportedOperation, f.fileno) + self.assertEqual(f.mode, gzip.READ) + self.assertIs(f.readable(), True) + self.assertIs(f.writable(), False) + self.assertIs(f.seekable(), True) + self.assertIs(f.closed, False) + self.assertIs(f.closed, True) + self.assertEqual(f.name, '') + self.assertRaises(AttributeError, f.fileno) + self.assertEqual(f.mode, gzip.READ) + self.assertIs(f.readable(), True) + self.assertIs(f.writable(), False) + self.assertIs(f.seekable(), True) + + def test_fileobj_and_filename(self): + filename2 = self.filename + 'new' + with (open(self.filename, 'wb') as fileobj, + gzip.GzipFile(fileobj=fileobj, filename=filename2, mode='wb') as f): + f.write(data1 * 50) + self.assertEqual(f.name, filename2) + with (open(self.filename, 'rb') as fileobj, + gzip.GzipFile(fileobj=fileobj, filename=filename2, mode='rb') as f): + self.assertEqual(f.read(), data1 * 50) + self.assertEqual(f.name, filename2) + # Sanity check that we are actually operating on the right file. + with gzip.GzipFile(self.filename, 'rb') as f: + self.assertEqual(f.read(), data1 * 50) + self.assertEqual(f.name, self.filename) def test_decompress_limited(self): """Decompressed data buffering should be limited""" @@ -529,7 +692,7 @@ def test_decompress_limited(self): self.assertEqual(decomp.read(1), b'\0') max_decomp = 1 + io.DEFAULT_BUFFER_SIZE self.assertLessEqual(decomp._buffer.raw.tell(), max_decomp, - "Excessive amount of data was decompressed") + "Excessive amount of data was decompressed") # Testing compress/decompress shortcut functions @@ -616,6 +779,66 @@ def test_issue44439(self): self.assertEqual(f.write(q), LENGTH) self.assertEqual(f.tell(), LENGTH) + def test_flush_flushes_compressor(self): + # See issue GH-105808. + b = io.BytesIO() + message = b"important message here." + with gzip.GzipFile(fileobj=b, mode='w') as f: + f.write(message) + f.flush() + partial_data = b.getvalue() + full_data = b.getvalue() + self.assertEqual(gzip.decompress(full_data), message) + # The partial data should contain the gzip header and the complete + # message, but not the end-of-stream markers (so we can't just + # decompress it directly). + with self.assertRaises(EOFError): + gzip.decompress(partial_data) + d = zlib.decompressobj(wbits=-zlib.MAX_WBITS) + f = io.BytesIO(partial_data) + gzip._read_gzip_header(f) + read_message = d.decompress(f.read()) + self.assertEqual(read_message, message) + + def test_flush_modes(self): + # Make sure the argument to flush is properly passed to the + # zlib.compressobj; see issue GH-105808. + class FakeCompressor: + def __init__(self): + self.modes = [] + def compress(self, data): + return b'' + def flush(self, mode=-1): + self.modes.append(mode) + return b'' + b = io.BytesIO() + fc = FakeCompressor() + with gzip.GzipFile(fileobj=b, mode='w') as f: + f.compress = fc + f.flush() + f.flush(50) + f.flush(zlib_mode=100) + # The implicit close will also flush the compressor. + expected_modes = [ + zlib.Z_SYNC_FLUSH, + 50, + 100, + -1, + ] + self.assertEqual(fc.modes, expected_modes) + + def test_write_seek_write(self): + # Make sure that offset is up-to-date before seeking + # See issue GH-108111 + b = io.BytesIO() + message = b"important message here." + with gzip.GzipFile(fileobj=b, mode='w') as f: + f.write(message) + f.seek(len(message)) + f.write(message) + data = b.getvalue() + self.assertEqual(gzip.decompress(data), message * 2) + class TestOpen(BaseTest): def test_binary_modes(self): @@ -646,13 +869,16 @@ def test_binary_modes(self): self.assertEqual(file_data, uncompressed) def test_pathlike_file(self): - filename = pathlib.Path(self.filename) + filename = os_helper.FakePath(self.filename) with gzip.open(filename, "wb") as f: f.write(data1 * 50) + self.assertEqual(f.name, self.filename) with gzip.open(filename, "ab") as f: f.write(data1) + self.assertEqual(f.name, self.filename) with gzip.open(filename) as f: self.assertEqual(f.read(), data1 * 51) + self.assertEqual(f.name, self.filename) def test_implicit_binary_modes(self): # Test implicit binary modes (no "b" or "t" in mode string). @@ -682,7 +908,6 @@ def test_implicit_binary_modes(self): file_data = gzip.decompress(f.read()) self.assertEqual(file_data, uncompressed) - @unittest.skipIf(sys.platform == 'win32', "TODO: RUSTPYTHON, windows text mode") def test_text_modes(self): uncompressed = data1.decode("ascii") * 50 uncompressed_raw = uncompressed.replace("\n", os.linesep) diff --git a/Lib/test/test_tarfile.py b/Lib/test/test_tarfile.py index 4ae81cb99f..973c9075ba 100644 --- a/Lib/test/test_tarfile.py +++ b/Lib/test/test_tarfile.py @@ -1,18 +1,25 @@ +import errno import sys import os import io from hashlib import sha256 -from contextlib import contextmanager +from contextlib import contextmanager, ExitStack from random import Random import pathlib +import shutil +import re +import warnings +import stat import unittest import unittest.mock import tarfile +from test import archiver_tests from test import support from test.support import os_helper from test.support import script_helper +from test.support import warnings_helper # Check for our compression modules. try: @@ -103,12 +110,12 @@ def test_fileobj_regular_file(self): with self.tar.extractfile(tarinfo) as fobj: data = fobj.read() self.assertEqual(len(data), tarinfo.size, - "regular file extraction failed") + "regular file extraction failed") self.assertEqual(sha256sum(data), sha256_regtype, - "regular file extraction failed") + "regular file extraction failed") def test_fileobj_readlines(self): - self.tar.extract("ustar/regtype", TEMPDIR) + self.tar.extract("ustar/regtype", TEMPDIR, filter='data') tarinfo = self.tar.getmember("ustar/regtype") with open(os.path.join(TEMPDIR, "ustar/regtype"), "r") as fobj1: lines1 = fobj1.readlines() @@ -117,26 +124,27 @@ def test_fileobj_readlines(self): fobj2 = io.TextIOWrapper(fobj) lines2 = fobj2.readlines() self.assertEqual(lines1, lines2, - "fileobj.readlines() failed") + "fileobj.readlines() failed") self.assertEqual(len(lines2), 114, - "fileobj.readlines() failed") + "fileobj.readlines() failed") self.assertEqual(lines2[83], - "I will gladly admit that Python is not the fastest " - "running scripting language.\n", - "fileobj.readlines() failed") + "I will gladly admit that Python is not the fastest " + "running scripting language.\n", + "fileobj.readlines() failed") def test_fileobj_iter(self): - self.tar.extract("ustar/regtype", TEMPDIR) + self.tar.extract("ustar/regtype", TEMPDIR, filter='data') tarinfo = self.tar.getmember("ustar/regtype") with open(os.path.join(TEMPDIR, "ustar/regtype"), "r") as fobj1: lines1 = fobj1.readlines() with self.tar.extractfile(tarinfo) as fobj2: lines2 = list(io.TextIOWrapper(fobj2)) self.assertEqual(lines1, lines2, - "fileobj.__iter__() failed") + "fileobj.__iter__() failed") def test_fileobj_seek(self): - self.tar.extract("ustar/regtype", TEMPDIR) + self.tar.extract("ustar/regtype", TEMPDIR, + filter='data') with open(os.path.join(TEMPDIR, "ustar/regtype"), "rb") as fobj: data = fobj.read() @@ -145,43 +153,43 @@ def test_fileobj_seek(self): text = fobj.read() fobj.seek(0) self.assertEqual(0, fobj.tell(), - "seek() to file's start failed") + "seek() to file's start failed") fobj.seek(2048, 0) self.assertEqual(2048, fobj.tell(), - "seek() to absolute position failed") + "seek() to absolute position failed") fobj.seek(-1024, 1) self.assertEqual(1024, fobj.tell(), - "seek() to negative relative position failed") + "seek() to negative relative position failed") fobj.seek(1024, 1) self.assertEqual(2048, fobj.tell(), - "seek() to positive relative position failed") + "seek() to positive relative position failed") s = fobj.read(10) self.assertEqual(s, data[2048:2058], - "read() after seek failed") + "read() after seek failed") fobj.seek(0, 2) self.assertEqual(tarinfo.size, fobj.tell(), - "seek() to file's end failed") + "seek() to file's end failed") self.assertEqual(fobj.read(), b"", - "read() at file's end did not return empty string") + "read() at file's end did not return empty string") fobj.seek(-tarinfo.size, 2) self.assertEqual(0, fobj.tell(), - "relative seek() to file's end failed") + "relative seek() to file's end failed") fobj.seek(512) s1 = fobj.readlines() fobj.seek(512) s2 = fobj.readlines() self.assertEqual(s1, s2, - "readlines() after seek failed") + "readlines() after seek failed") fobj.seek(0) self.assertEqual(len(fobj.readline()), fobj.tell(), - "tell() after readline() failed") + "tell() after readline() failed") fobj.seek(512) self.assertEqual(len(fobj.readline()) + 512, fobj.tell(), - "tell() after seek() and readline() failed") + "tell() after seek() and readline() failed") fobj.seek(0) line = fobj.readline() self.assertEqual(fobj.read(), data[len(line):], - "read() after readline() failed") + "read() after readline() failed") def test_fileobj_text(self): with self.tar.extractfile("ustar/regtype") as fobj: @@ -200,7 +208,7 @@ def test_fileobj_text(self): # supposed to be exported. def _test_fileobj_link(self, lnktype, regtype): with self.tar.extractfile(lnktype) as a, \ - self.tar.extractfile(regtype) as b: + self.tar.extractfile(regtype) as b: self.assertEqual(a.name, b.name) def test_fileobj_link1(self): @@ -225,13 +233,19 @@ def test_add_dir_getmember(self): self.add_dir_and_getmember('bar') self.add_dir_and_getmember('a'*101) + @unittest.skipUnless(hasattr(os, "getuid") and hasattr(os, "getgid"), + "Missing getuid or getgid implementation") def add_dir_and_getmember(self, name): + def filter(tarinfo): + tarinfo.uid = tarinfo.gid = 100 + return tarinfo + with os_helper.temp_cwd(): with tarfile.open(tmpname, 'w') as tar: tar.format = tarfile.USTAR_FORMAT try: os.mkdir(name) - tar.add(name) + tar.add(name, filter=filter) finally: os.rmdir(name) with tarfile.open(tmpname) as tar: @@ -256,8 +270,6 @@ class ListTest(ReadTest, unittest.TestCase): def setUp(self): self.tar = tarfile.open(self.tarname, mode=self.mode) - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_list(self): tio = io.TextIOWrapper(io.BytesIO(), 'ascii', newline='\n') with support.swap_attr(sys, 'stdout', tio): @@ -295,8 +307,6 @@ def conv(b): self.assertNotIn(b'link to', out) self.assertNotIn(b'->', out) - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_list_verbose(self): tio = io.TextIOWrapper(io.BytesIO(), 'ascii', newline='\n') with support.swap_attr(sys, 'stdout', tio): @@ -321,8 +331,6 @@ def test_list_verbose(self): self.assertIn(b'pax' + (b'/123' * 125) + b'/longlink link to pax' + (b'/123' * 125) + b'/longname', out) - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_list_members(self): tio = io.TextIOWrapper(io.BytesIO(), 'ascii', newline='\n') def members(tar): @@ -358,7 +366,7 @@ def test_is_tarfile_erroneous(self): self.assertFalse(tarfile.is_tarfile(tmpname)) # is_tarfile works on path-like objects - self.assertFalse(tarfile.is_tarfile(pathlib.Path(tmpname))) + self.assertFalse(tarfile.is_tarfile(os_helper.FakePath(tmpname))) # is_tarfile works on file objects with open(tmpname, "rb") as fobj: @@ -372,7 +380,7 @@ def test_is_tarfile_valid(self): self.assertTrue(tarfile.is_tarfile(self.tarname)) # is_tarfile works on path-like objects - self.assertTrue(tarfile.is_tarfile(pathlib.Path(self.tarname))) + self.assertTrue(tarfile.is_tarfile(os_helper.FakePath(self.tarname))) # is_tarfile works on file objects with open(self.tarname, "rb") as fobj: @@ -382,6 +390,18 @@ def test_is_tarfile_valid(self): with open(self.tarname, "rb") as fobj: self.assertTrue(tarfile.is_tarfile(io.BytesIO(fobj.read()))) + def test_is_tarfile_keeps_position(self): + # Test for issue44289: tarfile.is_tarfile() modifies + # file object's current position + with open(self.tarname, "rb") as fobj: + tarfile.is_tarfile(fobj) + self.assertEqual(fobj.tell(), 0) + + with open(self.tarname, "rb") as fobj: + file_like = io.BytesIO(fobj.read()) + tarfile.is_tarfile(file_like) + self.assertEqual(file_like.tell(), 0) + def test_empty_tarfile(self): # Test for issue6123: Allow opening empty archives. # This test checks if tarfile.open() is able to open an empty tar @@ -431,8 +451,8 @@ def test_ignore_zeros(self): tar = tarfile.open(tmpname, mode="r", ignore_zeros=True) try: self.assertListEqual(tar.getnames(), ["foo"], - "ignore_zeros=True should have skipped the %r-blocks" % - char) + "ignore_zeros=True should have skipped the %r-blocks" % + char) finally: tar.close() @@ -455,12 +475,11 @@ def test_premature_end_of_archive(self): t = tar.next() with self.assertRaisesRegex(tarfile.ReadError, "unexpected end of data"): - tar.extract(t, TEMPDIR) + tar.extract(t, TEMPDIR, filter='data') with self.assertRaisesRegex(tarfile.ReadError, "unexpected end of data"): tar.extractfile(t).read() - @unittest.skip("TODO: RUSTPYTHON, infinite recursion") def test_length_zero_header(self): # bpo-39017 (CVE-2019-20907): reading a zero-length header should fail # with an exception @@ -468,7 +487,32 @@ def test_length_zero_header(self): with tarfile.open(support.findfile('recursion.tar')) as tar: pass + def test_extractfile_attrs(self): + # gh-74468: TarFile.name must name a file, not a parent archive. + file = self.tar.getmember('ustar/regtype') + with self.tar.extractfile(file) as fobj: + self.assertEqual(fobj.name, 'ustar/regtype') + self.assertRaises(AttributeError, fobj.fileno) + self.assertIs(fobj.readable(), True) + self.assertIs(fobj.writable(), False) + if self.is_stream: + self.assertRaises(AttributeError, fobj.seekable) + else: + self.assertIs(fobj.seekable(), True) + self.assertIs(fobj.closed, False) + self.assertIs(fobj.closed, True) + self.assertEqual(fobj.name, 'ustar/regtype') + self.assertRaises(AttributeError, fobj.fileno) + self.assertIs(fobj.readable(), True) + self.assertIs(fobj.writable(), False) + if self.is_stream: + self.assertRaises(AttributeError, fobj.seekable) + else: + self.assertIs(fobj.seekable(), True) + + class MiscReadTestBase(CommonReadTest): + is_stream = False def requires_name_attribute(self): pass @@ -514,21 +558,23 @@ def test_bytes_name_attribute(self): self.assertIsInstance(tar.name, bytes) self.assertEqual(tar.name, os.path.abspath(fobj.name)) - def test_pathlike_name(self): - tarname = pathlib.Path(self.tarname) + def test_pathlike_name(self, tarname=None): + if tarname is None: + tarname = self.tarname + expected = os.path.abspath(tarname) + tarname = os_helper.FakePath(tarname) with tarfile.open(tarname, mode=self.mode) as tar: - self.assertIsInstance(tar.name, str) - self.assertEqual(tar.name, os.path.abspath(os.fspath(tarname))) + self.assertEqual(tar.name, expected) with self.taropen(tarname) as tar: - self.assertIsInstance(tar.name, str) - self.assertEqual(tar.name, os.path.abspath(os.fspath(tarname))) + self.assertEqual(tar.name, expected) with tarfile.TarFile.open(tarname, mode=self.mode) as tar: - self.assertIsInstance(tar.name, str) - self.assertEqual(tar.name, os.path.abspath(os.fspath(tarname))) + self.assertEqual(tar.name, expected) if self.suffix == '': with tarfile.TarFile(tarname, mode='r') as tar: - self.assertIsInstance(tar.name, str) - self.assertEqual(tar.name, os.path.abspath(os.fspath(tarname))) + self.assertEqual(tar.name, expected) + + def test_pathlike_bytes_name(self): + self.test_pathlike_name(os.fsencode(self.tarname)) def test_illegal_mode_arg(self): with open(tmpname, 'wb'): @@ -566,7 +612,7 @@ def test_fileobj_with_offset(self): # beginning works. tar.getmembers() self.assertEqual(tar.extractfile(t).read(), data, - "seek back did not work") + "seek back did not work") def test_fail_comp(self): # For Gzip and Bz2 Tests: fail with a ReadError on an uncompressed file. @@ -581,7 +627,7 @@ def test_v7_dirtype(self): # header with a "/" appended to the filename field. tarinfo = self.tar.getmember("misc/dirtype-old-v7") self.assertEqual(tarinfo.type, tarfile.DIRTYPE, - "v7 dirtype failed") + "v7 dirtype failed") def test_xstar_type(self): # The xstar format stores extra atime and ctime fields inside the @@ -595,15 +641,15 @@ def test_xstar_type(self): def test_check_members(self): for tarinfo in self.tar: self.assertEqual(int(tarinfo.mtime), 0o7606136617, - "wrong mtime for %s" % tarinfo.name) + "wrong mtime for %s" % tarinfo.name) if not tarinfo.name.startswith("ustar/"): continue self.assertEqual(tarinfo.uname, "tarfile", - "wrong uname for %s" % tarinfo.name) + "wrong uname for %s" % tarinfo.name) def test_find_members(self): self.assertEqual(self.tar.getmembers()[-1].name, "misc/eof", - "could not find all members") + "could not find all members") @unittest.skipUnless(hasattr(os, "link"), "Missing hardlink implementation") @@ -611,22 +657,22 @@ def test_find_members(self): def test_extract_hardlink(self): # Test hardlink extraction (e.g. bug #857297). with tarfile.open(tarname, errorlevel=1, encoding="iso8859-1") as tar: - tar.extract("ustar/regtype", TEMPDIR) + tar.extract("ustar/regtype", TEMPDIR, filter='data') self.addCleanup(os_helper.unlink, os.path.join(TEMPDIR, "ustar/regtype")) - tar.extract("ustar/lnktype", TEMPDIR) + tar.extract("ustar/lnktype", TEMPDIR, filter='data') self.addCleanup(os_helper.unlink, os.path.join(TEMPDIR, "ustar/lnktype")) with open(os.path.join(TEMPDIR, "ustar/lnktype"), "rb") as f: data = f.read() self.assertEqual(sha256sum(data), sha256_regtype) - tar.extract("ustar/symtype", TEMPDIR) + tar.extract("ustar/symtype", TEMPDIR, filter='data') self.addCleanup(os_helper.unlink, os.path.join(TEMPDIR, "ustar/symtype")) with open(os.path.join(TEMPDIR, "ustar/symtype"), "rb") as f: data = f.read() self.assertEqual(sha256sum(data), sha256_regtype) - @unittest.expectedFailureIfWindows("TODO: RUSTPYTHON") + @os_helper.skip_unless_working_chmod def test_extractall(self): # Test if extractall() correctly restores directory permissions # and times (see issue1735). @@ -635,13 +681,14 @@ def test_extractall(self): os.mkdir(DIR) try: directories = [t for t in tar if t.isdir()] - tar.extractall(DIR, directories) + tar.extractall(DIR, directories, filter='fully_trusted') for tarinfo in directories: path = os.path.join(DIR, tarinfo.name) if sys.platform != "win32": # Win32 has no support for fine grained permissions. self.assertEqual(tarinfo.mode & 0o777, - os.stat(path).st_mode & 0o777) + os.stat(path).st_mode & 0o777, + tarinfo.name) def format_mtime(mtime): if isinstance(mtime, float): return "{} ({})".format(mtime, mtime.hex()) @@ -657,7 +704,7 @@ def format_mtime(mtime): tar.close() os_helper.rmtree(DIR) - @unittest.expectedFailureIfWindows("TODO: RUSTPYTHON") + @os_helper.skip_unless_working_chmod def test_extract_directory(self): dirtype = "ustar/dirtype" DIR = os.path.join(TEMPDIR, "extractdir") @@ -665,7 +712,7 @@ def test_extract_directory(self): try: with tarfile.open(tarname, encoding="iso8859-1") as tar: tarinfo = tar.getmember(dirtype) - tar.extract(tarinfo, path=DIR) + tar.extract(tarinfo, path=DIR, filter='fully_trusted') extracted = os.path.join(DIR, dirtype) self.assertEqual(os.path.getmtime(extracted), tarinfo.mtime) if sys.platform != "win32": @@ -673,26 +720,49 @@ def test_extract_directory(self): finally: os_helper.rmtree(DIR) - @unittest.expectedFailureIfWindows("TODO: RUSTPYTHON") - def test_extractall_pathlike_name(self): + def test_deprecation_if_no_filter_passed_to_extractall(self): DIR = pathlib.Path(TEMPDIR) / "extractall" + with ( + os_helper.temp_dir(DIR), + tarfile.open(tarname, encoding="iso8859-1") as tar + ): + directories = [t for t in tar if t.isdir()] + with self.assertWarnsRegex(DeprecationWarning, "Use the filter argument") as cm: + tar.extractall(DIR, directories) + # check that the stacklevel of the deprecation warning is correct: + self.assertEqual(cm.filename, __file__) + + def test_deprecation_if_no_filter_passed_to_extract(self): + dirtype = "ustar/dirtype" + DIR = pathlib.Path(TEMPDIR) / "extractall" + with ( + os_helper.temp_dir(DIR), + tarfile.open(tarname, encoding="iso8859-1") as tar + ): + tarinfo = tar.getmember(dirtype) + with self.assertWarnsRegex(DeprecationWarning, "Use the filter argument") as cm: + tar.extract(tarinfo, path=DIR) + # check that the stacklevel of the deprecation warning is correct: + self.assertEqual(cm.filename, __file__) + + def test_extractall_pathlike_dir(self): + DIR = os.path.join(TEMPDIR, "extractall") with os_helper.temp_dir(DIR), \ - tarfile.open(tarname, encoding="iso8859-1") as tar: + tarfile.open(tarname, encoding="iso8859-1") as tar: directories = [t for t in tar if t.isdir()] - tar.extractall(DIR, directories) + tar.extractall(os_helper.FakePath(DIR), directories, filter='fully_trusted') for tarinfo in directories: - path = DIR / tarinfo.name + path = os.path.join(DIR, tarinfo.name) self.assertEqual(os.path.getmtime(path), tarinfo.mtime) - @unittest.expectedFailureIfWindows("TODO: RUSTPYTHON") - def test_extract_pathlike_name(self): + def test_extract_pathlike_dir(self): dirtype = "ustar/dirtype" - DIR = pathlib.Path(TEMPDIR) / "extractall" + DIR = os.path.join(TEMPDIR, "extractall") with os_helper.temp_dir(DIR), \ - tarfile.open(tarname, encoding="iso8859-1") as tar: + tarfile.open(tarname, encoding="iso8859-1") as tar: tarinfo = tar.getmember(dirtype) - tar.extract(tarinfo, path=DIR) - extracted = DIR / dirtype + tar.extract(tarinfo, path=os_helper.FakePath(DIR), filter='fully_trusted') + extracted = os.path.join(DIR, dirtype) self.assertEqual(os.path.getmtime(extracted), tarinfo.mtime) def test_init_close_fobj(self): @@ -731,6 +801,18 @@ def test_zlib_error_does_not_leak(self): with self.assertRaises(tarfile.ReadError): tarfile.open(self.tarname) + def test_next_on_empty_tarfile(self): + fd = io.BytesIO() + tf = tarfile.open(fileobj=fd, mode="w") + tf.close() + + fd.seek(0) + with tarfile.open(fileobj=fd, mode="r|") as tf: + self.assertEqual(tf.next(), None) + + fd.seek(0) + with tarfile.open(fileobj=fd, mode="r") as tf: + self.assertEqual(tf.next(), None) class MiscReadTest(MiscReadTestBase, unittest.TestCase): test_fail_comp = None @@ -750,6 +832,7 @@ def requires_name_attribute(self): class StreamReadTest(CommonReadTest, unittest.TestCase): prefix="r|" + is_stream = True def test_read_through(self): # Issue #11224: A poorly designed _FileInFile.read() method @@ -772,9 +855,9 @@ def test_fileobj_regular_file(self): with self.tar.extractfile(tarinfo) as fobj: data = fobj.read() self.assertEqual(len(data), tarinfo.size, - "regular file extraction failed") + "regular file extraction failed") self.assertEqual(sha256sum(data), sha256_regtype, - "regular file extraction failed") + "regular file extraction failed") def test_provoke_stream_error(self): tarinfos = self.tar.getmembers() @@ -804,7 +887,7 @@ def test_compare_members(self): continue self.assertIsNotNone(v2, "stream.extractfile() failed") self.assertEqual(v1.read(), v2.read(), - "stream extraction failed") + "stream extraction failed") finally: tar1.close() @@ -880,13 +963,30 @@ class LzmaDetectReadTest(LzmaTest, DetectReadTest): pass +class GzipBrokenHeaderCorrectException(GzipTest, unittest.TestCase): + """ + See: https://github.com/python/cpython/issues/107396 + """ + def runTest(self): + f = io.BytesIO( + b'\x1f\x8b' # header + b'\x08' # compression method + b'\x04' # flags + b'\0\0\0\0\0\0' # timestamp, compression data, OS ID + b'\0\x01' # size + b'\0\0\0\0\0' # corrupt data (zeros) + ) + with self.assertRaises(tarfile.ReadError): + tarfile.open(fileobj=f, mode='r|gz') + + class MemberReadTest(ReadTest, unittest.TestCase): def _test_member(self, tarinfo, chksum=None, **kwargs): if chksum is not None: with self.tar.extractfile(tarinfo) as f: self.assertEqual(sha256sum(f.read()), chksum, - "wrong sha256sum for %s" % tarinfo.name) + "wrong sha256sum for %s" % tarinfo.name) kwargs["mtime"] = 0o7606136617 kwargs["uid"] = 1000 @@ -897,7 +997,7 @@ def _test_member(self, tarinfo, chksum=None, **kwargs): kwargs["gname"] = "tarfile" for k, v in kwargs.items(): self.assertEqual(getattr(tarinfo, k), v, - "wrong value in %s field of %s" % (k, tarinfo.name)) + "wrong value in %s field of %s" % (k, tarinfo.name)) def test_find_regtype(self): tarinfo = self.tar.getmember("ustar/regtype") @@ -987,7 +1087,7 @@ def test_read_longname(self): except KeyError: self.fail("longname not found") self.assertNotEqual(tarinfo.type, tarfile.DIRTYPE, - "read longname as dirtype") + "read longname as dirtype") def test_read_longlink(self): longname = self.subdir + "/" + "123/" * 125 + "longname" @@ -1028,7 +1128,7 @@ def test_longname_directory(self): os.mkdir(longdir) tar.add(longdir) finally: - os.rmdir(longdir) + os.rmdir(longdir.rstrip("/")) with tarfile.open(tmpname) as tar: self.assertIsNotNone(tar.getmember(longdir)) self.assertIsNotNone(tar.getmember(longdir.removesuffix('/'))) @@ -1047,30 +1147,26 @@ class GNUReadTest(LongnameTest, ReadTest, unittest.TestCase): # an all platforms, and after that a test that will work only on # platforms/filesystems that prove to support sparse files. def _test_sparse_file(self, name): - self.tar.extract(name, TEMPDIR) + self.tar.extract(name, TEMPDIR, filter='data') filename = os.path.join(TEMPDIR, name) with open(filename, "rb") as fobj: data = fobj.read() self.assertEqual(sha256sum(data), sha256_sparse, - "wrong sha256sum for %s" % name) + "wrong sha256sum for %s" % name) if self._fs_supports_holes(): s = os.stat(filename) self.assertLess(s.st_blocks * 512, s.st_size) - @unittest.expectedFailureIf(sys.platform == "linux", "TODO: RUSTPYTHON") def test_sparse_file_old(self): self._test_sparse_file("gnu/sparse") - @unittest.expectedFailureIf(sys.platform == "linux", "TODO: RUSTPYTHON") def test_sparse_file_00(self): self._test_sparse_file("gnu/sparse-0.0") - @unittest.expectedFailureIf(sys.platform == "linux", "TODO: RUSTPYTHON") def test_sparse_file_01(self): self._test_sparse_file("gnu/sparse-0.1") - @unittest.expectedFailureIf(sys.platform == "linux", "TODO: RUSTPYTHON") def test_sparse_file_10(self): self._test_sparse_file("gnu/sparse-1.0") @@ -1141,6 +1237,48 @@ def test_pax_number_fields(self): finally: tar.close() + def test_pax_header_bad_formats(self): + # The fields from the pax header have priority over the + # TarInfo. + pax_header_replacements = ( + b" foo=bar\n", + b"0 \n", + b"1 \n", + b"2 \n", + b"3 =\n", + b"4 =a\n", + b"1000000 foo=bar\n", + b"0 foo=bar\n", + b"-12 foo=bar\n", + b"000000000000000000000000036 foo=bar\n", + ) + pax_headers = {"foo": "bar"} + + for replacement in pax_header_replacements: + with self.subTest(header=replacement): + tar = tarfile.open(tmpname, "w", format=tarfile.PAX_FORMAT, + encoding="iso8859-1") + try: + t = tarfile.TarInfo() + t.name = "pax" # non-ASCII + t.uid = 1 + t.pax_headers = pax_headers + tar.addfile(t) + finally: + tar.close() + + with open(tmpname, "rb") as f: + data = f.read() + self.assertIn(b"11 foo=bar\n", data) + data = data.replace(b"11 foo=bar\n", replacement) + + with open(tmpname, "wb") as f: + f.truncate() + f.write(data) + + with self.assertRaisesRegex(tarfile.ReadError, r"method tar: ReadError\('invalid header'\)"): + tarfile.open(tmpname, encoding="iso8859-1") + class WriteTestBase(TarTest): # Put all write tests in here that are supposed to be tested @@ -1192,7 +1330,7 @@ def test_100_char_name(self): tar = tarfile.open(tmpname) try: self.assertEqual(tar.getnames()[0], name, - "failed to store 100 char filename") + "failed to store 100 char filename") finally: tar.close() @@ -1207,7 +1345,7 @@ def test_tar_size(self): finally: tar.close() self.assertGreater(os.path.getsize(tmpname), 0, - "tarfile is empty") + "tarfile is empty") # The test_*_size tests test for bug #1167128. def test_file_size(self): @@ -1265,16 +1403,15 @@ def test_ordered_recursion(self): def test_gettarinfo_pathlike_name(self): with tarfile.open(tmpname, self.mode) as tar: - path = pathlib.Path(TEMPDIR) / "file" + path = os.path.join(TEMPDIR, "file") with open(path, "wb") as fobj: fobj.write(b"aaa") - tarinfo = tar.gettarinfo(path) - tarinfo2 = tar.gettarinfo(os.fspath(path)) + tarinfo = tar.gettarinfo(os_helper.FakePath(path)) + tarinfo2 = tar.gettarinfo(path) self.assertIsInstance(tarinfo.name, str) self.assertEqual(tarinfo.name, tarinfo2.name) self.assertEqual(tarinfo.size, 3) - @unittest.expectedFailureIfWindows("TODO: RUSTPYTHON") @unittest.skipUnless(hasattr(os, "link"), "Missing hardlink implementation") def test_link_size(self): @@ -1299,7 +1436,6 @@ def test_link_size(self): os_helper.unlink(target) os_helper.unlink(link) - @unittest.expectedFailureIfWindows("TODO: RUSTPYTHON") @os_helper.skip_unless_symlink def test_symlink_size(self): path = os.path.join(TEMPDIR, "symlink") @@ -1320,15 +1456,15 @@ def test_add_self(self): tar = tarfile.open(tmpname, self.mode) try: self.assertEqual(tar.name, dstname, - "archive name must be absolute") + "archive name must be absolute") tar.add(dstname) self.assertEqual(tar.getnames(), [], - "added the archive to itself") + "added the archive to itself") with os_helper.change_cwd(TEMPDIR): tar.add(dstname) self.assertEqual(tar.getnames(), [], - "added the archive to itself") + "added the archive to itself") finally: tar.close() @@ -1420,7 +1556,8 @@ def test_extractall_symlinks(self): with tarfile.open(temparchive, errorlevel=2) as tar: # this should not raise OSError: [Errno 17] File exists try: - tar.extractall(path=tempdir) + tar.extractall(path=tempdir, + filter='fully_trusted') except OSError: self.fail("extractall failed with symlinked files") finally: @@ -1486,16 +1623,7 @@ def write(self, data): class GzipWriteTest(GzipTest, WriteTest): - # TODO: RUSTPYTHON - def expectedSuccess(test_item): - test_item.__unittest_expecting_failure__ = False - return test_item - - # TODO: RUSTPYTHON - if sys.platform == "win32": - @expectedSuccess - def test_cwd(self): - super().test_cwd() + pass class Bz2WriteTest(Bz2Test, WriteTest): @@ -1525,10 +1653,14 @@ def test_stream_padding(self): with self.open(tmpname) as fobj: data = fobj.read() self.assertEqual(data.count(b"\0"), tarfile.RECORDSIZE, - "incorrect zero padding") + "incorrect zero padding") @unittest.skipUnless(sys.platform != "win32" and hasattr(os, "umask"), "Missing umask implementation") + @unittest.skipIf( + support.is_emscripten or support.is_wasi, + "Emscripten's/WASI's umask is a stub." + ) def test_file_mode(self): # Test for issue #8464: Create files with correct # permissions. @@ -1562,6 +1694,75 @@ class Bz2StreamWriteTest(Bz2Test, StreamWriteTest): class LzmaStreamWriteTest(LzmaTest, StreamWriteTest): decompressor = lzma.LZMADecompressor if lzma else None +class _CompressedWriteTest(TarTest): + # This is not actually a standalone test. + # It does not inherit WriteTest because it only makes sense with gz,bz2 + source = (b"And we move to Bristol where they have a special, " + + b"Very Silly candidate") + + def _compressed_tar(self, compresslevel): + fobj = io.BytesIO() + with tarfile.open(tmpname, self.mode, fobj, + compresslevel=compresslevel) as tarfl: + tarfl.addfile(tarfile.TarInfo("foo"), io.BytesIO(self.source)) + return fobj + + def _test_bz2_header(self, compresslevel): + fobj = self._compressed_tar(compresslevel) + self.assertEqual(fobj.getvalue()[0:10], + b"BZh%d1AY&SY" % compresslevel) + + def _test_gz_header(self, compresslevel): + fobj = self._compressed_tar(compresslevel) + self.assertEqual(fobj.getvalue()[:3], b"\x1f\x8b\x08") + +class Bz2CompressWriteTest(Bz2Test, _CompressedWriteTest, unittest.TestCase): + prefix = "w:" + def test_compression_levels(self): + self._test_bz2_header(1) + self._test_bz2_header(5) + self._test_bz2_header(9) + +class Bz2CompressStreamWriteTest(Bz2Test, _CompressedWriteTest, + unittest.TestCase): + prefix = "w|" + def test_compression_levels(self): + self._test_bz2_header(1) + self._test_bz2_header(5) + self._test_bz2_header(9) + +class GzCompressWriteTest(GzipTest, _CompressedWriteTest, unittest.TestCase): + prefix = "w:" + def test_compression_levels(self): + self._test_gz_header(1) + self._test_gz_header(5) + self._test_gz_header(9) + +class GzCompressStreamWriteTest(GzipTest, _CompressedWriteTest, + unittest.TestCase): + prefix = "w|" + def test_compression_levels(self): + self._test_gz_header(1) + self._test_gz_header(5) + self._test_gz_header(9) + +class CompressLevelRaises(unittest.TestCase): + def test_compresslevel_wrong_modes(self): + compresslevel = 5 + fobj = io.BytesIO() + with self.assertRaises(TypeError): + tarfile.open(tmpname, "w:", fobj, compresslevel=compresslevel) + + @support.requires_bz2() + def test_wrong_compresslevels(self): + # BZ2 checks that the compresslevel is in [1,9]. gz does not + fobj = io.BytesIO() + with self.assertRaises(ValueError): + tarfile.open(tmpname, "w:bz2", fobj, compresslevel=0) + with self.assertRaises(ValueError): + tarfile.open(tmpname, "w:bz2", fobj, compresslevel=10) + with self.assertRaises(ValueError): + tarfile.open(tmpname, "w|bz2", fobj, compresslevel=10) class GNUWriteTest(unittest.TestCase): # This testcase checks for correct creation of GNU Longname @@ -1606,11 +1807,11 @@ def _test(self, name, link=None): try: member = tar.next() self.assertIsNotNone(member, - "unable to read longname member") + "unable to read longname member") self.assertEqual(tarinfo.name, member.name, - "unable to read longname member") + "unable to read longname member") self.assertEqual(tarinfo.linkname, member.linkname, - "unable to read longname member") + "unable to read longname member") finally: tar.close() @@ -1753,10 +1954,10 @@ def test_create_existing_taropen(self): self.assertIn("spameggs42", names[0]) def test_create_pathlike_name(self): - with tarfile.open(pathlib.Path(tmpname), self.mode) as tobj: + with tarfile.open(os_helper.FakePath(tmpname), self.mode) as tobj: self.assertIsInstance(tobj.name, str) self.assertEqual(tobj.name, os.path.abspath(tmpname)) - tobj.add(pathlib.Path(self.file_path)) + tobj.add(os_helper.FakePath(self.file_path)) names = tobj.getnames() self.assertEqual(len(names), 1) self.assertIn('spameggs42', names[0]) @@ -1767,10 +1968,10 @@ def test_create_pathlike_name(self): self.assertIn('spameggs42', names[0]) def test_create_taropen_pathlike_name(self): - with self.taropen(pathlib.Path(tmpname), "x") as tobj: + with self.taropen(os_helper.FakePath(tmpname), "x") as tobj: self.assertIsInstance(tobj.name, str) self.assertEqual(tobj.name, os.path.abspath(tmpname)) - tobj.add(pathlib.Path(self.file_path)) + tobj.add(os_helper.FakePath(self.file_path)) names = tobj.getnames() self.assertEqual(len(names), 1) self.assertIn('spameggs42', names[0]) @@ -1845,19 +2046,18 @@ def test_add_twice(self): # time regardless of st_nlink. tarinfo = self.tar.gettarinfo(self.foo) self.assertEqual(tarinfo.type, tarfile.REGTYPE, - "add file as regular failed") + "add file as regular failed") - @unittest.expectedFailureIfWindows("TODO: RUSTPYTHON") def test_add_hardlink(self): tarinfo = self.tar.gettarinfo(self.bar) self.assertEqual(tarinfo.type, tarfile.LNKTYPE, - "add file as hardlink failed") + "add file as hardlink failed") def test_dereference_hardlink(self): self.tar.dereference = True tarinfo = self.tar.gettarinfo(self.bar) self.assertEqual(tarinfo.type, tarfile.REGTYPE, - "dereferencing hardlink failed") + "dereferencing hardlink failed") class PaxWriteTest(GNUWriteTest): @@ -1888,14 +2088,14 @@ def _test(self, name, link=None): def test_pax_global_header(self): pax_headers = { - "foo": "bar", - "uid": "0", - "mtime": "1.23", - "test": "\xe4\xf6\xfc", - "\xe4\xf6\xfc": "test"} + "foo": "bar", + "uid": "0", + "mtime": "1.23", + "test": "\xe4\xf6\xfc", + "\xe4\xf6\xfc": "test"} tar = tarfile.open(tmpname, "w", format=tarfile.PAX_FORMAT, - pax_headers=pax_headers) + pax_headers=pax_headers) try: tar.addfile(tarfile.TarInfo("test")) finally: @@ -1966,12 +2166,12 @@ def test_create_pax_header(self): self.assertEqual(info['uid'], 123) self.assertEqual(info['gid'], 124) self.assertEqual(header, - b'././@PaxHeader' + bytes(86) \ - + b'0000000\x000000000\x000000000\x0000000000020\x0000000000000\x00010205\x00 x' \ - + bytes(100) + b'ustar\x0000'+ bytes(247) \ - + b'16 mtime=1000.1\n' + bytes(496) + b'foo' + bytes(97) \ - + b'0000644\x000000173\x000000174\x0000000000144\x0000000001750\x00006516\x00 0' \ - + bytes(100) + b'ustar\x0000' + bytes(247)) + b'././@PaxHeader' + bytes(86) \ + + b'0000000\x000000000\x000000000\x0000000000020\x0000000000000\x00010205\x00 x' \ + + bytes(100) + b'ustar\x0000'+ bytes(247) \ + + b'16 mtime=1000.1\n' + bytes(496) + b'foo' + bytes(97) \ + + b'0000644\x000000173\x000000174\x0000000000144\x0000000001750\x00006516\x00 0' \ + + bytes(100) + b'ustar\x0000' + bytes(247)) # values that should be changed t = tarfile.TarInfo() @@ -1989,14 +2189,14 @@ def test_create_pax_header(self): self.assertEqual(info['uid'], 0) self.assertEqual(info['gid'], 0) self.assertEqual(header, - b'././@PaxHeader' + bytes(86) \ - + b'0000000\x000000000\x000000000\x0000000000130\x0000000000000\x00010207\x00 x' \ - + bytes(100) + b'ustar\x0000' + bytes(247) \ - + b'15 path=foo\xe3\x8d\xb4\n16 uid=16777216\n' \ - + b'16 gid=16777217\n20 size=10000000000\n' \ - + b'21 mtime=10000000000\n'+ bytes(424) + b'foo?' + bytes(96) \ - + b'0000644\x000000000\x000000000\x0000000000000\x0000000000000\x00006540\x00 0' \ - + bytes(100) + b'ustar\x0000' + bytes(247)) + b'././@PaxHeader' + bytes(86) \ + + b'0000000\x000000000\x000000000\x0000000000130\x0000000000000\x00010207\x00 x' \ + + bytes(100) + b'ustar\x0000' + bytes(247) \ + + b'15 path=foo\xe3\x8d\xb4\n16 uid=16777216\n' \ + + b'16 gid=16777217\n20 size=10000000000\n' \ + + b'21 mtime=10000000000\n'+ bytes(424) + b'foo?' + bytes(96) \ + + b'0000644\x000000000\x000000000\x0000000000000\x0000000000000\x00006540\x00 0' \ + + bytes(100) + b'ustar\x0000' + bytes(247)) class UnicodeTest: @@ -2004,8 +2204,6 @@ class UnicodeTest: def test_iso8859_1_filename(self): self._test_unicode_filename("iso8859-1") - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_utf7_filename(self): self._test_unicode_filename("utf7") @@ -2086,11 +2284,6 @@ class UstarUnicodeTest(UnicodeTest, unittest.TestCase): format = tarfile.USTAR_FORMAT - # TODO: RUSTPYTHON - @unittest.expectedFailure - def test_uname_unicode(self): - super().test_uname_unicode() - # Test whether the utf-8 encoded version of a filename exceeds the 100 # bytes name field limit (every occurrence of '\xff' will be expanded to 2 # bytes). @@ -2170,13 +2363,6 @@ class GNUUnicodeTest(UnicodeTest, unittest.TestCase): format = tarfile.GNU_FORMAT - # TODO: RUSTPYTHON - @unittest.expectedFailure - def test_uname_unicode(self): - super().test_uname_unicode() - - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_bad_pax_header(self): # Test for issue #8633. GNU tar <= 1.23 creates raw binary fields # without a hdrcharset=BINARY header. @@ -2198,8 +2384,6 @@ class PAXUnicodeTest(UnicodeTest, unittest.TestCase): # PAX_FORMAT ignores encoding in write mode. test_unicode_filename_error = None - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_binary_header(self): # Test a POSIX.1-2008 compatible header with a hdrcharset=BINARY field. for encoding, name in ( @@ -2446,8 +2630,6 @@ def test__all__(self): 'SubsequentHeaderError', 'ExFileObject', 'main'} support.check__all__(self, tarfile, not_exported=not_exported) - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_useful_error_message_when_modules_missing(self): fname = os.path.join(os.path.dirname(__file__), 'testtar.tar.xz') with self.assertRaises(tarfile.ReadError) as excinfo: @@ -2472,14 +2654,24 @@ def tarfilecmd_failure(self, *args): return script_helper.assert_python_failure('-m', 'tarfile', *args) def make_simple_tarfile(self, tar_name): - files = [support.findfile('tokenize_tests.txt'), + files = [support.findfile('tokenize_tests.txt', + subdir='tokenizedata'), support.findfile('tokenize_tests-no-coding-cookie-' - 'and-utf8-bom-sig-only.txt')] + 'and-utf8-bom-sig-only.txt', + subdir='tokenizedata')] self.addCleanup(os_helper.unlink, tar_name) with tarfile.open(tar_name, 'w') as tf: for tardata in files: tf.add(tardata, arcname=os.path.basename(tardata)) + def make_evil_tarfile(self, tar_name): + self.addCleanup(os_helper.unlink, tar_name) + with tarfile.open(tar_name, 'w') as tf: + benign = tarfile.TarInfo('benign') + tf.addfile(benign, fileobj=io.BytesIO(b'')) + evil = tarfile.TarInfo('../evil') + tf.addfile(evil, fileobj=io.BytesIO(b'')) + def test_bad_use(self): rc, out, err = self.tarfilecmd_failure() self.assertEqual(out, b'') @@ -2523,8 +2715,6 @@ def test_test_command_invalid_file(self): finally: os_helper.unlink(tmpname) - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_list_command(self): for tar_name in testtarnames: with support.captured_stdout() as t: @@ -2536,8 +2726,6 @@ def test_list_command(self): PYTHONIOENCODING='ascii') self.assertEqual(out, expected) - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_list_command_verbose(self): for tar_name in testtarnames: with support.captured_stdout() as t: @@ -2557,9 +2745,11 @@ def test_list_command_invalid_file(self): self.assertEqual(rc, 1) def test_create_command(self): - files = [support.findfile('tokenize_tests.txt'), + files = [support.findfile('tokenize_tests.txt', + subdir='tokenizedata'), support.findfile('tokenize_tests-no-coding-cookie-' - 'and-utf8-bom-sig-only.txt')] + 'and-utf8-bom-sig-only.txt', + subdir='tokenizedata')] for opt in '-c', '--create': try: out = self.tarfilecmd(opt, tmpname, *files) @@ -2570,9 +2760,11 @@ def test_create_command(self): os_helper.unlink(tmpname) def test_create_command_verbose(self): - files = [support.findfile('tokenize_tests.txt'), + files = [support.findfile('tokenize_tests.txt', + subdir='tokenizedata'), support.findfile('tokenize_tests-no-coding-cookie-' - 'and-utf8-bom-sig-only.txt')] + 'and-utf8-bom-sig-only.txt', + subdir='tokenizedata')] for opt in '-v', '--verbose': try: out = self.tarfilecmd(opt, '-c', tmpname, *files, @@ -2584,7 +2776,7 @@ def test_create_command_verbose(self): os_helper.unlink(tmpname) def test_create_command_dotless_filename(self): - files = [support.findfile('tokenize_tests.txt')] + files = [support.findfile('tokenize_tests.txt', subdir='tokenizedata')] try: out = self.tarfilecmd('-c', dotlessname, *files) self.assertEqual(out, b'') @@ -2595,7 +2787,7 @@ def test_create_command_dotless_filename(self): def test_create_command_dot_started_filename(self): tar_name = os.path.join(TEMPDIR, ".testtar") - files = [support.findfile('tokenize_tests.txt')] + files = [support.findfile('tokenize_tests.txt', subdir='tokenizedata')] try: out = self.tarfilecmd('-c', tar_name, *files) self.assertEqual(out, b'') @@ -2605,9 +2797,11 @@ def test_create_command_dot_started_filename(self): os_helper.unlink(tar_name) def test_create_command_compressed(self): - files = [support.findfile('tokenize_tests.txt'), + files = [support.findfile('tokenize_tests.txt', + subdir='tokenizedata'), support.findfile('tokenize_tests-no-coding-cookie-' - 'and-utf8-bom-sig-only.txt')] + 'and-utf8-bom-sig-only.txt', + subdir='tokenizedata')] for filetype in (GzipTest, Bz2Test, LzmaTest): if not filetype.open: continue @@ -2640,6 +2834,25 @@ def test_extract_command_verbose(self): finally: os_helper.rmtree(tarextdir) + def test_extract_command_filter(self): + self.make_evil_tarfile(tmpname) + # Make an inner directory, so the member named '../evil' + # is still extracted into `tarextdir` + destdir = os.path.join(tarextdir, 'dest') + os.mkdir(tarextdir) + try: + with os_helper.temp_cwd(destdir): + self.tarfilecmd_failure('-e', tmpname, + '-v', + '--filter', 'data') + out = self.tarfilecmd('-e', tmpname, + '-v', + '--filter', 'fully_trusted', + PYTHONIOENCODING='utf-8') + self.assertIn(b' file is extracted.', out) + finally: + os_helper.rmtree(tarextdir) + def test_extract_command_different_directory(self): self.make_simple_tarfile(tmpname) try: @@ -2692,7 +2905,7 @@ def test_no_eof(self): except: pass self.assertEqual(os.path.getsize(tmpname), 0, - "context manager wrote an end-of-archive block") + "context manager wrote an end-of-archive block") self.assertTrue(tar.closed, "context manager failed") def test_eof(self): @@ -2701,7 +2914,7 @@ def test_eof(self): with tarfile.open(tmpname, "w"): pass self.assertNotEqual(os.path.getsize(tmpname), 0, - "context manager wrote no end-of-archive block") + "context manager wrote no end-of-archive block") def test_fileobj(self): # Test that __exit__() did not close the external file @@ -2723,7 +2936,7 @@ class LinkEmulationTest(ReadTest, unittest.TestCase): # symbolic or hard links tarfile tries to extract these types of members # as the regular files they point to. def _test_link_extraction(self, name): - self.tar.extract(name, TEMPDIR) + self.tar.extract(name, TEMPDIR, filter='fully_trusted') with open(os.path.join(TEMPDIR, name), "rb") as f: data = f.read() self.assertEqual(sha256sum(data), sha256_regtype) @@ -2855,8 +3068,10 @@ def test_extract_with_numeric_owner(self, mock_geteuid, mock_chmod, mock_chown): with self._setup_test(mock_geteuid) as (tarfl, filename_1, _, filename_2): - tarfl.extract(filename_1, TEMPDIR, numeric_owner=True) - tarfl.extract(filename_2 , TEMPDIR, numeric_owner=True) + tarfl.extract(filename_1, TEMPDIR, numeric_owner=True, + filter='fully_trusted') + tarfl.extract(filename_2 , TEMPDIR, numeric_owner=True, + filter='fully_trusted') # convert to filesystem paths f_filename_1 = os.path.join(TEMPDIR, filename_1) @@ -2874,7 +3089,8 @@ def test_extractall_with_numeric_owner(self, mock_geteuid, mock_chmod, mock_chown): with self._setup_test(mock_geteuid) as (tarfl, filename_1, dirname_1, filename_2): - tarfl.extractall(TEMPDIR, numeric_owner=True) + tarfl.extractall(TEMPDIR, numeric_owner=True, + filter='fully_trusted') # convert to filesystem paths f_filename_1 = os.path.join(TEMPDIR, filename_1) @@ -2899,7 +3115,8 @@ def test_extractall_with_numeric_owner(self, mock_geteuid, mock_chmod, def test_extract_without_numeric_owner(self, mock_geteuid, mock_chmod, mock_chown): with self._setup_test(mock_geteuid) as (tarfl, filename_1, _, _): - tarfl.extract(filename_1, TEMPDIR, numeric_owner=False) + tarfl.extract(filename_1, TEMPDIR, numeric_owner=False, + filter='fully_trusted') # convert to filesystem paths f_filename_1 = os.path.join(TEMPDIR, filename_1) @@ -2913,6 +3130,1086 @@ def test_keyword_only(self, mock_geteuid): tarfl.extract, filename_1, TEMPDIR, False, True) +class ReplaceTests(ReadTest, unittest.TestCase): + def test_replace_name(self): + member = self.tar.getmember('ustar/regtype') + replaced = member.replace(name='misc/other') + self.assertEqual(replaced.name, 'misc/other') + self.assertEqual(member.name, 'ustar/regtype') + self.assertEqual(self.tar.getmember('ustar/regtype').name, + 'ustar/regtype') + + def test_replace_deep(self): + member = self.tar.getmember('pax/regtype1') + replaced = member.replace() + replaced.pax_headers['gname'] = 'not-bar' + self.assertEqual(member.pax_headers['gname'], 'bar') + self.assertEqual( + self.tar.getmember('pax/regtype1').pax_headers['gname'], 'bar') + + def test_replace_shallow(self): + member = self.tar.getmember('pax/regtype1') + replaced = member.replace(deep=False) + replaced.pax_headers['gname'] = 'not-bar' + self.assertEqual(member.pax_headers['gname'], 'not-bar') + self.assertEqual( + self.tar.getmember('pax/regtype1').pax_headers['gname'], 'not-bar') + + def test_replace_all(self): + member = self.tar.getmember('ustar/regtype') + for attr_name in ('name', 'mtime', 'mode', 'linkname', + 'uid', 'gid', 'uname', 'gname'): + with self.subTest(attr_name=attr_name): + replaced = member.replace(**{attr_name: None}) + self.assertEqual(getattr(replaced, attr_name), None) + self.assertNotEqual(getattr(member, attr_name), None) + + def test_replace_internal(self): + member = self.tar.getmember('ustar/regtype') + with self.assertRaises(TypeError): + member.replace(offset=123456789) + + +class NoneInfoExtractTests(ReadTest): + # These mainly check that all kinds of members are extracted successfully + # if some metadata is None. + # Some of the methods do additional spot checks. + + # We also test that the default filters can deal with None. + + extraction_filter = None + + @classmethod + def setUpClass(cls): + tar = tarfile.open(tarname, mode='r', encoding="iso8859-1") + cls.control_dir = pathlib.Path(TEMPDIR) / "extractall_ctrl" + tar.errorlevel = 0 + with ExitStack() as cm: + if cls.extraction_filter is None: + cm.enter_context(warnings.catch_warnings( + action="ignore", category=DeprecationWarning)) + tar.extractall(cls.control_dir, filter=cls.extraction_filter) + tar.close() + cls.control_paths = set( + p.relative_to(cls.control_dir) + for p in pathlib.Path(cls.control_dir).glob('**/*')) + + @classmethod + def tearDownClass(cls): + shutil.rmtree(cls.control_dir) + + def check_files_present(self, directory): + got_paths = set( + p.relative_to(directory) + for p in pathlib.Path(directory).glob('**/*')) + self.assertEqual(self.control_paths, got_paths) + + @contextmanager + def extract_with_none(self, *attr_names): + DIR = pathlib.Path(TEMPDIR) / "extractall_none" + self.tar.errorlevel = 0 + for member in self.tar.getmembers(): + for attr_name in attr_names: + setattr(member, attr_name, None) + with os_helper.temp_dir(DIR): + self.tar.extractall(DIR, filter='fully_trusted') + self.check_files_present(DIR) + yield DIR + + def test_extractall_none_mtime(self): + # mtimes of extracted files should be later than 'now' -- the mtime + # of a previously created directory. + now = pathlib.Path(TEMPDIR).stat().st_mtime + with self.extract_with_none('mtime') as DIR: + for path in pathlib.Path(DIR).glob('**/*'): + with self.subTest(path=path): + try: + mtime = path.stat().st_mtime + except OSError: + # Some systems can't stat symlinks, ignore those + if not path.is_symlink(): + raise + else: + self.assertGreaterEqual(path.stat().st_mtime, now) + + def test_extractall_none_mode(self): + # modes of directories and regular files should match the mode + # of a "normally" created directory or regular file + dir_mode = pathlib.Path(TEMPDIR).stat().st_mode + regular_file = pathlib.Path(TEMPDIR) / 'regular_file' + regular_file.write_text('') + regular_file_mode = regular_file.stat().st_mode + with self.extract_with_none('mode') as DIR: + for path in pathlib.Path(DIR).glob('**/*'): + with self.subTest(path=path): + if path.is_dir(): + self.assertEqual(path.stat().st_mode, dir_mode) + elif path.is_file(): + self.assertEqual(path.stat().st_mode, + regular_file_mode) + + def test_extractall_none_uid(self): + with self.extract_with_none('uid'): + pass + + def test_extractall_none_gid(self): + with self.extract_with_none('gid'): + pass + + def test_extractall_none_uname(self): + with self.extract_with_none('uname'): + pass + + def test_extractall_none_gname(self): + with self.extract_with_none('gname'): + pass + + def test_extractall_none_ownership(self): + with self.extract_with_none('uid', 'gid', 'uname', 'gname'): + pass + +class NoneInfoExtractTests_Data(NoneInfoExtractTests, unittest.TestCase): + extraction_filter = 'data' + +class NoneInfoExtractTests_FullyTrusted(NoneInfoExtractTests, + unittest.TestCase): + extraction_filter = 'fully_trusted' + +class NoneInfoExtractTests_Tar(NoneInfoExtractTests, unittest.TestCase): + extraction_filter = 'tar' + +class NoneInfoExtractTests_Default(NoneInfoExtractTests, + unittest.TestCase): + extraction_filter = None + +class NoneInfoTests_Misc(unittest.TestCase): + def test_add(self): + # When addfile() encounters None metadata, it raises a ValueError + bio = io.BytesIO() + for tarformat in (tarfile.USTAR_FORMAT, tarfile.GNU_FORMAT, + tarfile.PAX_FORMAT): + with self.subTest(tarformat=tarformat): + tar = tarfile.open(fileobj=bio, mode='w', format=tarformat) + tarinfo = tar.gettarinfo(tarname) + try: + tar.addfile(tarinfo) + except Exception: + if tarformat == tarfile.USTAR_FORMAT: + # In the old, limited format, adding might fail for + # reasons like the UID being too large + pass + else: + raise + else: + for attr_name in ('mtime', 'mode', 'uid', 'gid', + 'uname', 'gname'): + with self.subTest(attr_name=attr_name): + replaced = tarinfo.replace(**{attr_name: None}) + with self.assertRaisesRegex(ValueError, + f"{attr_name}"): + tar.addfile(replaced) + + def test_list(self): + # Change some metadata to None, then compare list() output + # word-for-word. We want list() to not raise, and to only change + # printout for the affected piece of metadata. + # (n.b.: some contents of the test archive are hardcoded.) + for attr_names in ({'mtime'}, {'mode'}, {'uid'}, {'gid'}, + {'uname'}, {'gname'}, + {'uid', 'uname'}, {'gid', 'gname'}): + with (self.subTest(attr_names=attr_names), + tarfile.open(tarname, encoding="iso8859-1") as tar): + tio_prev = io.TextIOWrapper(io.BytesIO(), 'ascii', newline='\n') + with support.swap_attr(sys, 'stdout', tio_prev): + tar.list() + for member in tar.getmembers(): + for attr_name in attr_names: + setattr(member, attr_name, None) + tio_new = io.TextIOWrapper(io.BytesIO(), 'ascii', newline='\n') + with support.swap_attr(sys, 'stdout', tio_new): + tar.list() + for expected, got in zip(tio_prev.detach().getvalue().split(), + tio_new.detach().getvalue().split()): + if attr_names == {'mtime'} and re.match(rb'2003-01-\d\d', expected): + self.assertEqual(got, b'????-??-??') + elif attr_names == {'mtime'} and re.match(rb'\d\d:\d\d:\d\d', expected): + self.assertEqual(got, b'??:??:??') + elif attr_names == {'mode'} and re.match( + rb'.([r-][w-][x-]){3}', expected): + self.assertEqual(got, b'??????????') + elif attr_names == {'uname'} and expected.startswith( + (b'tarfile/', b'lars/', b'foo/')): + exp_user, exp_group = expected.split(b'/') + got_user, got_group = got.split(b'/') + self.assertEqual(got_group, exp_group) + self.assertRegex(got_user, b'[0-9]+') + elif attr_names == {'gname'} and expected.endswith( + (b'/tarfile', b'/users', b'/bar')): + exp_user, exp_group = expected.split(b'/') + got_user, got_group = got.split(b'/') + self.assertEqual(got_user, exp_user) + self.assertRegex(got_group, b'[0-9]+') + elif attr_names == {'uid'} and expected.startswith( + (b'1000/')): + exp_user, exp_group = expected.split(b'/') + got_user, got_group = got.split(b'/') + self.assertEqual(got_group, exp_group) + self.assertEqual(got_user, b'None') + elif attr_names == {'gid'} and expected.endswith((b'/100')): + exp_user, exp_group = expected.split(b'/') + got_user, got_group = got.split(b'/') + self.assertEqual(got_user, exp_user) + self.assertEqual(got_group, b'None') + elif attr_names == {'uid', 'uname'} and expected.startswith( + (b'tarfile/', b'lars/', b'foo/', b'1000/')): + exp_user, exp_group = expected.split(b'/') + got_user, got_group = got.split(b'/') + self.assertEqual(got_group, exp_group) + self.assertEqual(got_user, b'None') + elif attr_names == {'gname', 'gid'} and expected.endswith( + (b'/tarfile', b'/users', b'/bar', b'/100')): + exp_user, exp_group = expected.split(b'/') + got_user, got_group = got.split(b'/') + self.assertEqual(got_user, exp_user) + self.assertEqual(got_group, b'None') + else: + # In other cases the output should be the same + self.assertEqual(expected, got) + +def _filemode_to_int(mode): + """Inverse of `stat.filemode` (for permission bits) + + Using mode strings rather than numbers makes the later tests more readable. + """ + str_mode = mode[1:] + result = ( + {'r': stat.S_IRUSR, '-': 0}[str_mode[0]] + | {'w': stat.S_IWUSR, '-': 0}[str_mode[1]] + | {'x': stat.S_IXUSR, '-': 0, + 's': stat.S_IXUSR | stat.S_ISUID, + 'S': stat.S_ISUID}[str_mode[2]] + | {'r': stat.S_IRGRP, '-': 0}[str_mode[3]] + | {'w': stat.S_IWGRP, '-': 0}[str_mode[4]] + | {'x': stat.S_IXGRP, '-': 0, + 's': stat.S_IXGRP | stat.S_ISGID, + 'S': stat.S_ISGID}[str_mode[5]] + | {'r': stat.S_IROTH, '-': 0}[str_mode[6]] + | {'w': stat.S_IWOTH, '-': 0}[str_mode[7]] + | {'x': stat.S_IXOTH, '-': 0, + 't': stat.S_IXOTH | stat.S_ISVTX, + 'T': stat.S_ISVTX}[str_mode[8]] + ) + # check we did this right + assert stat.filemode(result)[1:] == mode[1:] + + return result + +class ArchiveMaker: + """Helper to create a tar file with specific contents + + Usage: + + with ArchiveMaker() as t: + t.add('filename', ...) + + with t.open() as tar: + ... # `tar` is now a TarFile with 'filename' in it! + """ + def __init__(self): + self.bio = io.BytesIO() + + def __enter__(self): + self.tar_w = tarfile.TarFile(mode='w', fileobj=self.bio) + return self + + def __exit__(self, *exc): + self.tar_w.close() + self.contents = self.bio.getvalue() + self.bio = None + + def add(self, name, *, type=None, symlink_to=None, hardlink_to=None, + mode=None, size=None, **kwargs): + """Add a member to the test archive. Call within `with`.""" + name = str(name) + tarinfo = tarfile.TarInfo(name).replace(**kwargs) + if size is not None: + tarinfo.size = size + if mode: + tarinfo.mode = _filemode_to_int(mode) + if symlink_to is not None: + type = tarfile.SYMTYPE + tarinfo.linkname = str(symlink_to) + if hardlink_to is not None: + type = tarfile.LNKTYPE + tarinfo.linkname = str(hardlink_to) + if name.endswith('/') and type is None: + type = tarfile.DIRTYPE + if type is not None: + tarinfo.type = type + if tarinfo.isreg(): + fileobj = io.BytesIO(bytes(tarinfo.size)) + else: + fileobj = None + self.tar_w.addfile(tarinfo, fileobj) + + def open(self, **kwargs): + """Open the resulting archive as TarFile. Call after `with`.""" + bio = io.BytesIO(self.contents) + return tarfile.open(fileobj=bio, **kwargs) + +# Under WASI, `os_helper.can_symlink` is False to make +# `skip_unless_symlink` skip symlink tests. " +# But in the following tests we use can_symlink to *determine* which +# behavior is expected. +# Like other symlink tests, skip these on WASI for now. +if support.is_wasi: + def symlink_test(f): + return unittest.skip("WASI: Skip symlink test for now")(f) +else: + def symlink_test(f): + return f + + +class TestExtractionFilters(unittest.TestCase): + + # A temporary directory for the extraction results. + # All files that "escape" the destination path should still end + # up in this directory. + outerdir = pathlib.Path(TEMPDIR) / 'outerdir' + + # The destination for the extraction, within `outerdir` + destdir = outerdir / 'dest' + + @contextmanager + def check_context(self, tar, filter): + """Extracts `tar` to `self.destdir` and allows checking the result + + If an error occurs, it must be checked using `expect_exception` + + Otherwise, all resulting files must be checked using `expect_file`, + except the destination directory itself and parent directories of + other files. + When checking directories, do so before their contents. + """ + with os_helper.temp_dir(self.outerdir): + try: + tar.extractall(self.destdir, filter=filter) + except Exception as exc: + self.raised_exception = exc + self.expected_paths = set() + else: + self.raised_exception = None + self.expected_paths = set(self.outerdir.glob('**/*')) + self.expected_paths.discard(self.destdir) + try: + yield + finally: + tar.close() + if self.raised_exception: + raise self.raised_exception + self.assertEqual(self.expected_paths, set()) + + def expect_file(self, name, type=None, symlink_to=None, mode=None, + size=None): + """Check a single file. See check_context.""" + if self.raised_exception: + raise self.raised_exception + # use normpath() rather than resolve() so we don't follow symlinks + path = pathlib.Path(os.path.normpath(self.destdir / name)) + self.assertIn(path, self.expected_paths) + self.expected_paths.remove(path) + if mode is not None and os_helper.can_chmod() and os.name != 'nt': + got = stat.filemode(stat.S_IMODE(path.stat().st_mode)) + self.assertEqual(got, mode) + if type is None and isinstance(name, str) and name.endswith('/'): + type = tarfile.DIRTYPE + if symlink_to is not None: + got = (self.destdir / name).readlink() + expected = pathlib.Path(symlink_to) + # The symlink might be the same (textually) as what we expect, + # but some systems change the link to an equivalent path, so + # we fall back to samefile(). + if expected != got: + self.assertTrue(got.samefile(expected)) + elif type == tarfile.REGTYPE or type is None: + self.assertTrue(path.is_file()) + elif type == tarfile.DIRTYPE: + self.assertTrue(path.is_dir()) + elif type == tarfile.FIFOTYPE: + self.assertTrue(path.is_fifo()) + else: + raise NotImplementedError(type) + if size is not None: + self.assertEqual(path.stat().st_size, size) + for parent in path.parents: + self.expected_paths.discard(parent) + + def expect_exception(self, exc_type, message_re='.'): + with self.assertRaisesRegex(exc_type, message_re): + if self.raised_exception is not None: + raise self.raised_exception + self.raised_exception = None + + def test_benign_file(self): + with ArchiveMaker() as arc: + arc.add('benign.txt') + for filter in 'fully_trusted', 'tar', 'data': + with self.check_context(arc.open(), filter): + self.expect_file('benign.txt') + + def test_absolute(self): + # Test handling a member with an absolute path + # Inspired by 'absolute1' in https://github.com/jwilk/traversal-archives + with ArchiveMaker() as arc: + arc.add(self.outerdir / 'escaped.evil') + + with self.check_context(arc.open(), 'fully_trusted'): + self.expect_file('../escaped.evil') + + for filter in 'tar', 'data': + with self.check_context(arc.open(), filter): + if str(self.outerdir).startswith('/'): + # We strip leading slashes, as e.g. GNU tar does + # (without --absolute-filenames). + outerdir_stripped = str(self.outerdir).lstrip('/') + self.expect_file(f'{outerdir_stripped}/escaped.evil') + else: + # On this system, absolute paths don't have leading + # slashes. + # So, there's nothing to strip. We refuse to unpack + # to an absolute path, nonetheless. + self.expect_exception( + tarfile.AbsolutePathError, + """['"].*escaped.evil['"] has an absolute path""") + + @symlink_test + def test_parent_symlink(self): + # Test interplaying symlinks + # Inspired by 'dirsymlink2a' in jwilk/traversal-archives + with ArchiveMaker() as arc: + + # `current` links to `.` which is both: + # - the destination directory + # - `current` itself + arc.add('current', symlink_to='.') + + # effectively points to ./../ + arc.add('parent', symlink_to='current/..') + + arc.add('parent/evil') + + if os_helper.can_symlink(): + with self.check_context(arc.open(), 'fully_trusted'): + if self.raised_exception is not None: + # Windows will refuse to create a file that's a symlink to itself + # (and tarfile doesn't swallow that exception) + self.expect_exception(FileExistsError) + # The other cases will fail with this error too. + # Skip the rest of this test. + return + else: + self.expect_file('current', symlink_to='.') + self.expect_file('parent', symlink_to='current/..') + self.expect_file('../evil') + + with self.check_context(arc.open(), 'tar'): + self.expect_exception( + tarfile.OutsideDestinationError, + """'parent/evil' would be extracted to ['"].*evil['"], """ + + "which is outside the destination") + + with self.check_context(arc.open(), 'data'): + self.expect_exception( + tarfile.LinkOutsideDestinationError, + """'parent' would link to ['"].*outerdir['"], """ + + "which is outside the destination") + + else: + # No symlink support. The symlinks are ignored. + with self.check_context(arc.open(), 'fully_trusted'): + self.expect_file('parent/evil') + with self.check_context(arc.open(), 'tar'): + self.expect_file('parent/evil') + with self.check_context(arc.open(), 'data'): + self.expect_file('parent/evil') + + @symlink_test + def test_parent_symlink2(self): + # Test interplaying symlinks + # Inspired by 'dirsymlink2b' in jwilk/traversal-archives + + # Posix and Windows have different pathname resolution: + # either symlink or a '..' component resolve first. + # Let's see which we are on. + if os_helper.can_symlink(): + testpath = os.path.join(TEMPDIR, 'resolution_test') + os.mkdir(testpath) + + # testpath/current links to `.` which is all of: + # - `testpath` + # - `testpath/current` + # - `testpath/current/current` + # - etc. + os.symlink('.', os.path.join(testpath, 'current')) + + # we'll test where `testpath/current/../file` ends up + with open(os.path.join(testpath, 'current', '..', 'file'), 'w'): + pass + + if os.path.exists(os.path.join(testpath, 'file')): + # Windows collapses 'current\..' to '.' first, leaving + # 'testpath\file' + dotdot_resolves_early = True + elif os.path.exists(os.path.join(testpath, '..', 'file')): + # Posix resolves 'current' to '.' first, leaving + # 'testpath/../file' + dotdot_resolves_early = False + else: + raise AssertionError('Could not determine link resolution') + + with ArchiveMaker() as arc: + + # `current` links to `.` which is both the destination directory + # and `current` itself + arc.add('current', symlink_to='.') + + # `current/parent` is also available as `./parent`, + # and effectively points to `./../` + arc.add('current/parent', symlink_to='..') + + arc.add('parent/evil') + + with self.check_context(arc.open(), 'fully_trusted'): + if os_helper.can_symlink(): + self.expect_file('current', symlink_to='.') + self.expect_file('parent', symlink_to='..') + self.expect_file('../evil') + else: + self.expect_file('current/') + self.expect_file('parent/evil') + + with self.check_context(arc.open(), 'tar'): + if os_helper.can_symlink(): + # Fail when extracting a file outside destination + self.expect_exception( + tarfile.OutsideDestinationError, + "'parent/evil' would be extracted to " + + """['"].*evil['"], which is outside """ + + "the destination") + else: + self.expect_file('current/') + self.expect_file('parent/evil') + + with self.check_context(arc.open(), 'data'): + if os_helper.can_symlink(): + if dotdot_resolves_early: + # Fail when extracting a file outside destination + self.expect_exception( + tarfile.OutsideDestinationError, + "'parent/evil' would be extracted to " + + """['"].*evil['"], which is outside """ + + "the destination") + else: + # Fail as soon as we have a symlink outside the destination + self.expect_exception( + tarfile.LinkOutsideDestinationError, + "'current/parent' would link to " + + """['"].*outerdir['"], which is outside """ + + "the destination") + else: + self.expect_file('current/') + self.expect_file('parent/evil') + + @symlink_test + def test_absolute_symlink(self): + # Test symlink to an absolute path + # Inspired by 'dirsymlink' in jwilk/traversal-archives + with ArchiveMaker() as arc: + arc.add('parent', symlink_to=self.outerdir) + arc.add('parent/evil') + + with self.check_context(arc.open(), 'fully_trusted'): + if os_helper.can_symlink(): + self.expect_file('parent', symlink_to=self.outerdir) + self.expect_file('../evil') + else: + self.expect_file('parent/evil') + + with self.check_context(arc.open(), 'tar'): + if os_helper.can_symlink(): + self.expect_exception( + tarfile.OutsideDestinationError, + "'parent/evil' would be extracted to " + + """['"].*evil['"], which is outside """ + + "the destination") + else: + self.expect_file('parent/evil') + + with self.check_context(arc.open(), 'data'): + self.expect_exception( + tarfile.AbsoluteLinkError, + "'parent' is a link to an absolute path") + + def test_absolute_hardlink(self): + # Test hardlink to an absolute path + # Inspired by 'dirsymlink' in https://github.com/jwilk/traversal-archives + with ArchiveMaker() as arc: + arc.add('parent', hardlink_to=self.outerdir / 'foo') + + with self.check_context(arc.open(), 'fully_trusted'): + self.expect_exception(KeyError, ".*foo. not found") + + with self.check_context(arc.open(), 'tar'): + self.expect_exception(KeyError, ".*foo. not found") + + with self.check_context(arc.open(), 'data'): + self.expect_exception( + tarfile.AbsoluteLinkError, + "'parent' is a link to an absolute path") + + @symlink_test + def test_sly_relative0(self): + # Inspired by 'relative0' in jwilk/traversal-archives + with ArchiveMaker() as arc: + # points to `../../tmp/moo` + arc.add('../moo', symlink_to='..//tmp/moo') + + try: + with self.check_context(arc.open(), filter='fully_trusted'): + if os_helper.can_symlink(): + if isinstance(self.raised_exception, FileExistsError): + # XXX TarFile happens to fail creating a parent + # directory. + # This might be a bug, but fixing it would hurt + # security. + # Note that e.g. GNU `tar` rejects '..' components, + # so you could argue this is an invalid archive and we + # just raise an bad type of exception. + self.expect_exception(FileExistsError) + else: + self.expect_file('../moo', symlink_to='..//tmp/moo') + else: + # The symlink can't be extracted and is ignored + pass + except FileExistsError: + pass + + for filter in 'tar', 'data': + with self.check_context(arc.open(), filter): + self.expect_exception( + tarfile.OutsideDestinationError, + "'../moo' would be extracted to " + + "'.*moo', which is outside " + + "the destination") + + @symlink_test + def test_sly_relative2(self): + # Inspired by 'relative2' in jwilk/traversal-archives + with ArchiveMaker() as arc: + arc.add('tmp/') + arc.add('tmp/../../moo', symlink_to='tmp/../..//tmp/moo') + + with self.check_context(arc.open(), 'fully_trusted'): + self.expect_file('tmp', type=tarfile.DIRTYPE) + if os_helper.can_symlink(): + self.expect_file('../moo', symlink_to='tmp/../../tmp/moo') + + for filter in 'tar', 'data': + with self.check_context(arc.open(), filter): + self.expect_exception( + tarfile.OutsideDestinationError, + "'tmp/../../moo' would be extracted to " + + """['"].*moo['"], which is outside the """ + + "destination") + + @symlink_test + def test_deep_symlink(self): + # Test that symlinks and hardlinks inside a directory + # point to the correct file (`target` of size 3). + # If links aren't supported we get a copy of the file. + with ArchiveMaker() as arc: + arc.add('targetdir/target', size=3) + # a hardlink's linkname is relative to the archive + arc.add('linkdir/hardlink', hardlink_to=os.path.join( + 'targetdir', 'target')) + # a symlink's linkname is relative to the link's directory + arc.add('linkdir/symlink', symlink_to=os.path.join( + '..', 'targetdir', 'target')) + + for filter in 'tar', 'data', 'fully_trusted': + with self.check_context(arc.open(), filter): + self.expect_file('targetdir/target', size=3) + self.expect_file('linkdir/hardlink', size=3) + if os_helper.can_symlink(): + self.expect_file('linkdir/symlink', size=3, + symlink_to='../targetdir/target') + else: + self.expect_file('linkdir/symlink', size=3) + + @symlink_test + def test_chains(self): + # Test chaining of symlinks/hardlinks. + # Symlinks are created before the files they point to. + with ArchiveMaker() as arc: + arc.add('linkdir/symlink', symlink_to='hardlink') + arc.add('symlink2', symlink_to=os.path.join( + 'linkdir', 'hardlink2')) + arc.add('targetdir/target', size=3) + arc.add('linkdir/hardlink', hardlink_to='targetdir/target') + arc.add('linkdir/hardlink2', hardlink_to='linkdir/symlink') + + for filter in 'tar', 'data', 'fully_trusted': + with self.check_context(arc.open(), filter): + self.expect_file('targetdir/target', size=3) + self.expect_file('linkdir/hardlink', size=3) + self.expect_file('linkdir/hardlink2', size=3) + if os_helper.can_symlink(): + self.expect_file('linkdir/symlink', size=3, + symlink_to='hardlink') + self.expect_file('symlink2', size=3, + symlink_to='linkdir/hardlink2') + else: + self.expect_file('linkdir/symlink', size=3) + self.expect_file('symlink2', size=3) + + def test_modes(self): + # Test how file modes are extracted + # (Note that the modes are ignored on platforms without working chmod) + with ArchiveMaker() as arc: + arc.add('all_bits', mode='?rwsrwsrwt') + arc.add('perm_bits', mode='?rwxrwxrwx') + arc.add('exec_group_other', mode='?rw-rwxrwx') + arc.add('read_group_only', mode='?---r-----') + arc.add('no_bits', mode='?---------') + arc.add('dir/', mode='?---rwsrwt') + + # On some systems, setting the sticky bit is a no-op. + # Check if that's the case. + tmp_filename = os.path.join(TEMPDIR, "tmp.file") + with open(tmp_filename, 'w'): + pass + try: + try: + os.chmod(tmp_filename, + os.stat(tmp_filename).st_mode | stat.S_ISVTX) + except OSError as exc: + if exc.errno == getattr(errno, "EFTYPE", 0): + # gh-108948: On FreeBSD, regular users cannot set + # the sticky bit. + self.skipTest("chmod() failed with EFTYPE: " + "regular users cannot set sticky bit") + else: + raise + have_sticky_files = (os.stat(tmp_filename).st_mode & stat.S_ISVTX) + finally: + os.unlink(tmp_filename) + + os.mkdir(tmp_filename) + os.chmod(tmp_filename, os.stat(tmp_filename).st_mode | stat.S_ISVTX) + have_sticky_dirs = (os.stat(tmp_filename).st_mode & stat.S_ISVTX) + os.rmdir(tmp_filename) + + with self.check_context(arc.open(), 'fully_trusted'): + if have_sticky_files: + self.expect_file('all_bits', mode='?rwsrwsrwt') + else: + self.expect_file('all_bits', mode='?rwsrwsrwx') + self.expect_file('perm_bits', mode='?rwxrwxrwx') + self.expect_file('exec_group_other', mode='?rw-rwxrwx') + self.expect_file('read_group_only', mode='?---r-----') + self.expect_file('no_bits', mode='?---------') + if have_sticky_dirs: + self.expect_file('dir/', mode='?---rwsrwt') + else: + self.expect_file('dir/', mode='?---rwsrwx') + + with self.check_context(arc.open(), 'tar'): + self.expect_file('all_bits', mode='?rwxr-xr-x') + self.expect_file('perm_bits', mode='?rwxr-xr-x') + self.expect_file('exec_group_other', mode='?rw-r-xr-x') + self.expect_file('read_group_only', mode='?---r-----') + self.expect_file('no_bits', mode='?---------') + self.expect_file('dir/', mode='?---r-xr-x') + + with self.check_context(arc.open(), 'data'): + normal_dir_mode = stat.filemode(stat.S_IMODE( + self.outerdir.stat().st_mode)) + self.expect_file('all_bits', mode='?rwxr-xr-x') + self.expect_file('perm_bits', mode='?rwxr-xr-x') + self.expect_file('exec_group_other', mode='?rw-r--r--') + self.expect_file('read_group_only', mode='?rw-r-----') + self.expect_file('no_bits', mode='?rw-------') + self.expect_file('dir/', mode=normal_dir_mode) + + def test_pipe(self): + # Test handling of a special file + with ArchiveMaker() as arc: + arc.add('foo', type=tarfile.FIFOTYPE) + + for filter in 'fully_trusted', 'tar': + with self.check_context(arc.open(), filter): + if hasattr(os, 'mkfifo'): + self.expect_file('foo', type=tarfile.FIFOTYPE) + else: + # The pipe can't be extracted and is skipped. + pass + + with self.check_context(arc.open(), 'data'): + self.expect_exception( + tarfile.SpecialFileError, + "'foo' is a special file") + + def test_special_files(self): + # Creating device files is tricky. Instead of attempting that let's + # only check the filter result. + for special_type in tarfile.FIFOTYPE, tarfile.CHRTYPE, tarfile.BLKTYPE: + tarinfo = tarfile.TarInfo('foo') + tarinfo.type = special_type + trusted = tarfile.fully_trusted_filter(tarinfo, '') + self.assertIs(trusted, tarinfo) + tar = tarfile.tar_filter(tarinfo, '') + self.assertEqual(tar.type, special_type) + with self.assertRaises(tarfile.SpecialFileError) as cm: + tarfile.data_filter(tarinfo, '') + self.assertIsInstance(cm.exception.tarinfo, tarfile.TarInfo) + self.assertEqual(cm.exception.tarinfo.name, 'foo') + + def test_fully_trusted_filter(self): + # The 'fully_trusted' filter returns the original TarInfo objects. + with tarfile.TarFile.open(tarname) as tar: + for tarinfo in tar.getmembers(): + filtered = tarfile.fully_trusted_filter(tarinfo, '') + self.assertIs(filtered, tarinfo) + + def test_tar_filter(self): + # The 'tar' filter returns TarInfo objects with the same name/type. + # (It can also fail for particularly "evil" input, but we don't have + # that in the test archive.) + with tarfile.TarFile.open(tarname) as tar: + for tarinfo in tar.getmembers(): + filtered = tarfile.tar_filter(tarinfo, '') + self.assertIs(filtered.name, tarinfo.name) + self.assertIs(filtered.type, tarinfo.type) + + def test_data_filter(self): + # The 'data' filter either raises, or returns TarInfo with the same + # name/type. + with tarfile.TarFile.open(tarname) as tar: + for tarinfo in tar.getmembers(): + try: + filtered = tarfile.data_filter(tarinfo, '') + except tarfile.FilterError: + continue + self.assertIs(filtered.name, tarinfo.name) + self.assertIs(filtered.type, tarinfo.type) + + def test_default_filter_warns(self): + """Ensure the default filter warns""" + with ArchiveMaker() as arc: + arc.add('foo') + with warnings_helper.check_warnings( + ('Python 3.14', DeprecationWarning)): + with self.check_context(arc.open(), None): + self.expect_file('foo') + + def test_change_default_filter_on_instance(self): + tar = tarfile.TarFile(tarname, 'r') + def strict_filter(tarinfo, path): + if tarinfo.name == 'ustar/regtype': + return tarinfo + else: + return None + tar.extraction_filter = strict_filter + with self.check_context(tar, None): + self.expect_file('ustar/regtype') + + def test_change_default_filter_on_class(self): + def strict_filter(tarinfo, path): + if tarinfo.name == 'ustar/regtype': + return tarinfo + else: + return None + tar = tarfile.TarFile(tarname, 'r') + with support.swap_attr(tarfile.TarFile, 'extraction_filter', + staticmethod(strict_filter)): + with self.check_context(tar, None): + self.expect_file('ustar/regtype') + + def test_change_default_filter_on_subclass(self): + class TarSubclass(tarfile.TarFile): + def extraction_filter(self, tarinfo, path): + if tarinfo.name == 'ustar/regtype': + return tarinfo + else: + return None + + tar = TarSubclass(tarname, 'r') + with self.check_context(tar, None): + self.expect_file('ustar/regtype') + + def test_change_default_filter_to_string(self): + tar = tarfile.TarFile(tarname, 'r') + tar.extraction_filter = 'data' + with self.check_context(tar, None): + self.expect_exception(TypeError) + + def test_custom_filter(self): + def custom_filter(tarinfo, path): + self.assertIs(path, self.destdir) + if tarinfo.name == 'move_this': + return tarinfo.replace(name='moved') + if tarinfo.name == 'ignore_this': + return None + return tarinfo + + with ArchiveMaker() as arc: + arc.add('move_this') + arc.add('ignore_this') + arc.add('keep') + with self.check_context(arc.open(), custom_filter): + self.expect_file('moved') + self.expect_file('keep') + + def test_bad_filter_name(self): + with ArchiveMaker() as arc: + arc.add('foo') + with self.check_context(arc.open(), 'bad filter name'): + self.expect_exception(ValueError) + + def test_stateful_filter(self): + # Stateful filters should be possible. + # (This doesn't really test tarfile. Rather, it demonstrates + # that third parties can implement a stateful filter.) + class StatefulFilter: + def __enter__(self): + self.num_files_processed = 0 + return self + + def __call__(self, tarinfo, path): + try: + tarinfo = tarfile.data_filter(tarinfo, path) + except tarfile.FilterError: + return None + self.num_files_processed += 1 + return tarinfo + + def __exit__(self, *exc_info): + self.done = True + + with ArchiveMaker() as arc: + arc.add('good') + arc.add('bad', symlink_to='/') + arc.add('good') + with StatefulFilter() as custom_filter: + with self.check_context(arc.open(), custom_filter): + self.expect_file('good') + self.assertEqual(custom_filter.num_files_processed, 2) + self.assertEqual(custom_filter.done, True) + + def test_errorlevel(self): + def extracterror_filter(tarinfo, path): + raise tarfile.ExtractError('failed with ExtractError') + def filtererror_filter(tarinfo, path): + raise tarfile.FilterError('failed with FilterError') + def oserror_filter(tarinfo, path): + raise OSError('failed with OSError') + def tarerror_filter(tarinfo, path): + raise tarfile.TarError('failed with base TarError') + def valueerror_filter(tarinfo, path): + raise ValueError('failed with ValueError') + + with ArchiveMaker() as arc: + arc.add('file') + + # If errorlevel is 0, errors affected by errorlevel are ignored + + with self.check_context(arc.open(errorlevel=0), extracterror_filter): + self.expect_file('file') + + with self.check_context(arc.open(errorlevel=0), filtererror_filter): + self.expect_file('file') + + with self.check_context(arc.open(errorlevel=0), oserror_filter): + self.expect_file('file') + + with self.check_context(arc.open(errorlevel=0), tarerror_filter): + self.expect_exception(tarfile.TarError) + + with self.check_context(arc.open(errorlevel=0), valueerror_filter): + self.expect_exception(ValueError) + + # If 1, all fatal errors are raised + + with self.check_context(arc.open(errorlevel=1), extracterror_filter): + self.expect_file('file') + + with self.check_context(arc.open(errorlevel=1), filtererror_filter): + self.expect_exception(tarfile.FilterError) + + with self.check_context(arc.open(errorlevel=1), oserror_filter): + self.expect_exception(OSError) + + with self.check_context(arc.open(errorlevel=1), tarerror_filter): + self.expect_exception(tarfile.TarError) + + with self.check_context(arc.open(errorlevel=1), valueerror_filter): + self.expect_exception(ValueError) + + # If 2, all non-fatal errors are raised as well. + + with self.check_context(arc.open(errorlevel=2), extracterror_filter): + self.expect_exception(tarfile.ExtractError) + + with self.check_context(arc.open(errorlevel=2), filtererror_filter): + self.expect_exception(tarfile.FilterError) + + with self.check_context(arc.open(errorlevel=2), oserror_filter): + self.expect_exception(OSError) + + with self.check_context(arc.open(errorlevel=2), tarerror_filter): + self.expect_exception(tarfile.TarError) + + with self.check_context(arc.open(errorlevel=2), valueerror_filter): + self.expect_exception(ValueError) + + # We only handle ExtractionError, FilterError & OSError specially. + + with self.check_context(arc.open(errorlevel='boo!'), filtererror_filter): + self.expect_exception(TypeError) # errorlevel is not int + + +class OverwriteTests(archiver_tests.OverwriteTests, unittest.TestCase): + testdir = os.path.join(TEMPDIR, "testoverwrite") + + @classmethod + def setUpClass(cls): + p = cls.ar_with_file = os.path.join(TEMPDIR, 'tar-with-file.tar') + cls.addClassCleanup(os_helper.unlink, p) + with tarfile.open(p, 'w') as tar: + t = tarfile.TarInfo('test') + t.size = 10 + tar.addfile(t, io.BytesIO(b'newcontent')) + + p = cls.ar_with_dir = os.path.join(TEMPDIR, 'tar-with-dir.tar') + cls.addClassCleanup(os_helper.unlink, p) + with tarfile.open(p, 'w') as tar: + tar.addfile(tar.gettarinfo(os.curdir, 'test')) + + p = os.path.join(TEMPDIR, 'tar-with-implicit-dir.tar') + cls.ar_with_implicit_dir = p + cls.addClassCleanup(os_helper.unlink, p) + with tarfile.open(p, 'w') as tar: + t = tarfile.TarInfo('test/file') + t.size = 10 + tar.addfile(t, io.BytesIO(b'newcontent')) + + def open(self, path): + return tarfile.open(path, 'r') + + def extractall(self, ar): + ar.extractall(self.testdir, filter='fully_trusted') + + def setUpModule(): os_helper.unlink(TEMPDIR) os.makedirs(TEMPDIR) diff --git a/Lib/test/test_xmlrpc.py b/Lib/test/test_xmlrpc.py index 25a4be0e03..8f1e0d0f0c 100644 --- a/Lib/test/test_xmlrpc.py +++ b/Lib/test/test_xmlrpc.py @@ -25,6 +25,8 @@ except ImportError: gzip = None +support.requires_working_socket(module=True) + alist = [{'astring': 'foo@bar.baz.spam', 'afloat': 7283.43, 'anint': 2**20, @@ -38,22 +40,18 @@ 'ukey\u4000': 'regular value', 'datetime1': xmlrpclib.DateTime('20050210T11:41:23'), 'datetime2': xmlrpclib.DateTime( - (2005, 2, 10, 11, 41, 23, 0, 1, -1)), + (2005, 2, 10, 11, 41, 23, 0, 1, -1)), 'datetime3': xmlrpclib.DateTime( - datetime.datetime(2005, 2, 10, 11, 41, 23)), + datetime.datetime(2005, 2, 10, 11, 41, 23)), }] class XMLRPCTestCase(unittest.TestCase): - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_dump_load(self): dump = xmlrpclib.dumps((alist,)) load = xmlrpclib.loads(dump) self.assertEqual(alist, load[0][0]) - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_dump_bare_datetime(self): # This checks that an unwrapped datetime.date object can be handled # by the marshalling code. This can't be done via test_dump_load() @@ -88,8 +86,6 @@ def test_dump_bare_datetime(self): self.assertIsNone(m) - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_datetime_before_1900(self): # same as before but with a date before 1900 dt = datetime.datetime(1, 2, 10, 11, 41, 23) @@ -108,20 +104,16 @@ def test_datetime_before_1900(self): self.assertIs(type(newdt), xmlrpclib.DateTime) self.assertIsNone(m) - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_bug_1164912 (self): d = xmlrpclib.DateTime() ((new_d,), dummy) = xmlrpclib.loads(xmlrpclib.dumps((d,), - methodresponse=True)) + methodresponse=True)) self.assertIsInstance(new_d.value, str) # Check that the output of dumps() is still an 8-bit string s = xmlrpclib.dumps((new_d,), methodresponse=True) self.assertIsInstance(s, str) - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_newstyle_class(self): class T(object): pass @@ -187,21 +179,17 @@ def dummy_write(s): m.dump_double(xmlrpclib.MAXINT + 42, dummy_write) m.dump_double(xmlrpclib.MININT - 42, dummy_write) - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_dump_none(self): value = alist + [None] arg1 = (alist + [None],) strg = xmlrpclib.dumps(arg1, allow_none=True) self.assertEqual(value, - xmlrpclib.loads(strg)[0][0]) + xmlrpclib.loads(strg)[0][0]) self.assertRaises(TypeError, xmlrpclib.dumps, (arg1,)) - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_dump_encoding(self): value = {'key\u20ac\xa4': - 'value\u20ac\xa4'} + 'value\u20ac\xa4'} strg = xmlrpclib.dumps((value,), encoding='iso-8859-15') strg = "" + strg self.assertEqual(xmlrpclib.loads(strg)[0][0], value) @@ -220,8 +208,6 @@ def test_dump_encoding(self): self.assertEqual(xmlrpclib.loads(strg)[0][0], value) self.assertEqual(xmlrpclib.loads(strg)[1], methodname) - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_dump_bytes(self): sample = b"my dog has fleas" self.assertEqual(sample, xmlrpclib.Binary(sample)) @@ -241,8 +227,6 @@ def test_dump_bytes(self): self.assertIs(type(newvalue), xmlrpclib.Binary) self.assertIsNone(m) - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_loads_unsupported(self): ResponseError = xmlrpclib.ResponseError data = '' @@ -265,8 +249,6 @@ def check_loads(self, s, value, **kwargs): self.assertIs(type(newvalue), type(value)) self.assertIsNone(m) - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_load_standard_types(self): check = self.check_loads check('string', 'string') @@ -294,8 +276,6 @@ def test_load_standard_types(self): 'a1' '', {'a': 1, 'b': 2}) - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_load_extension_types(self): check = self.check_loads check('', None) @@ -309,12 +289,22 @@ def test_load_extension_types(self): check('9876543210.0123456789', decimal.Decimal('9876543210.0123456789')) + def test_limit_int(self): + check = self.check_loads + maxdigits = 5000 + with support.adjust_int_max_str_digits(maxdigits): + s = '1' * (maxdigits + 1) + with self.assertRaises(ValueError): + check(f'{s}', None) + with self.assertRaises(ValueError): + check(f'{s}', None) + def test_get_host_info(self): # see bug #3613, this raised a TypeError transp = xmlrpc.client.Transport() self.assertEqual(transp.get_host_info("user@host.tld"), - ('host.tld', - [('Authorization', 'Basic dXNlcg==')], {})) + ('host.tld', + [('Authorization', 'Basic dXNlcg==')], {})) def test_ssl_presence(self): try: @@ -330,8 +320,6 @@ def test_ssl_presence(self): except OSError: self.assertTrue(has_ssl) - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_keepalive_disconnect(self): class RequestHandler(http.server.BaseHTTPRequestHandler): protocol_version = "HTTP/1.1" @@ -471,8 +459,6 @@ def test_repr(self): self.assertEqual(repr(f), "") self.assertEqual(repr(f), str(f)) - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_dump_fault(self): f = xmlrpclib.Fault(42, 'Test Fault') s = xmlrpclib.dumps((f,)) @@ -814,8 +800,6 @@ def tearDown(self): xmlrpc.server.SimpleXMLRPCServer._send_traceback_header = False class SimpleServerTestCase(BaseServerTestCase): - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_simple1(self): try: p = xmlrpclib.ServerProxy(URL) @@ -826,8 +810,6 @@ def test_simple1(self): # protocol error; provide additional information in test output self.fail("%s\n%s" % (e, getattr(e, "headers", ""))) - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_nonascii(self): start_string = 'P\N{LATIN SMALL LETTER Y WITH CIRCUMFLEX}t' end_string = 'h\N{LATIN SMALL LETTER O WITH HORN}n' @@ -841,8 +823,6 @@ def test_nonascii(self): # protocol error; provide additional information in test output self.fail("%s\n%s" % (e, getattr(e, "headers", ""))) - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_client_encoding(self): start_string = '\u20ac' end_string = '\xa4' @@ -857,8 +837,6 @@ def test_client_encoding(self): # protocol error; provide additional information in test output self.fail("%s\n%s" % (e, getattr(e, "headers", ""))) - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_nonascii_methodname(self): try: p = xmlrpclib.ServerProxy(URL, encoding='ascii') @@ -879,8 +857,6 @@ def test_404(self): self.assertEqual(response.status, 404) self.assertEqual(response.reason, 'Not Found') - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_introspection1(self): expected_methods = set(['pow', 'div', 'my_function', 'add', 'têšt', 'system.listMethods', 'system.methodHelp', @@ -897,8 +873,6 @@ def test_introspection1(self): self.fail("%s\n%s" % (e, getattr(e, "headers", ""))) - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_introspection2(self): try: # test _methodHelp() @@ -911,10 +885,8 @@ def test_introspection2(self): # protocol error; provide additional information in test output self.fail("%s\n%s" % (e, getattr(e, "headers", ""))) - # TODO: RUSTPYTHON - @unittest.expectedFailure @make_request_and_skipIf(sys.flags.optimize >= 2, - "Docstrings are omitted with -O2 and above") + "Docstrings are omitted with -O2 and above") def test_introspection3(self): try: # test native doc @@ -927,8 +899,6 @@ def test_introspection3(self): # protocol error; provide additional information in test output self.fail("%s\n%s" % (e, getattr(e, "headers", ""))) - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_introspection4(self): # the SimpleXMLRPCServer doesn't support signatures, but # at least check that we can try making the call @@ -942,8 +912,6 @@ def test_introspection4(self): # protocol error; provide additional information in test output self.fail("%s\n%s" % (e, getattr(e, "headers", ""))) - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_multicall(self): try: p = xmlrpclib.ServerProxy(URL) @@ -961,8 +929,6 @@ def test_multicall(self): # protocol error; provide additional information in test output self.fail("%s\n%s" % (e, getattr(e, "headers", ""))) - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_non_existing_multicall(self): try: p = xmlrpclib.ServerProxy(URL) @@ -976,16 +942,14 @@ def test_non_existing_multicall(self): self.assertEqual(result.results[0]['faultCode'], 1) self.assertEqual(result.results[0]['faultString'], - ':method "this_is_not_exists" ' - 'is not supported') + ':method "this_is_not_exists" ' + 'is not supported') except (xmlrpclib.ProtocolError, OSError) as e: # ignore failures due to non-blocking socket 'unavailable' errors if not is_unavailable_exception(e): # protocol error; provide additional information in test output self.fail("%s\n%s" % (e, getattr(e, "headers", ""))) - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_dotted_attribute(self): # Raises an AttributeError because private methods are not allowed. self.assertRaises(AttributeError, @@ -996,16 +960,12 @@ def test_dotted_attribute(self): # This avoids waiting for the socket timeout. self.test_simple1() - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_allow_dotted_names_true(self): # XXX also need allow_dotted_names_false test. server = xmlrpclib.ServerProxy("http://%s:%d/RPC2" % (ADDR, PORT)) data = server.Fixture.getData() self.assertEqual(data, '42') - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_unicode_host(self): server = xmlrpclib.ServerProxy("http://%s:%d/RPC2" % (ADDR, PORT)) self.assertEqual(server.add("a", "\xe9"), "a\xe9") @@ -1020,8 +980,6 @@ def test_partial_post(self): 'Accept-Encoding: identity\r\n' 'Content-Length: 0\r\n\r\n'.encode('ascii')) - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_context_manager(self): with xmlrpclib.ServerProxy(URL) as server: server.add(2, 3) @@ -1030,8 +988,6 @@ def test_context_manager(self): self.assertEqual(server('transport')._connection, (None, None)) - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_context_manager_method_error(self): try: with xmlrpclib.ServerProxy(URL) as server: @@ -1047,8 +1003,6 @@ class SimpleServerEncodingTestCase(BaseServerTestCase): def threadFunc(evt, numrequests, requestHandler=None, encoding=None): http_server(evt, numrequests, requestHandler, 'iso-8859-15') - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_server_encoding(self): start_string = '\u20ac' end_string = '\xa4' @@ -1067,70 +1021,57 @@ def test_server_encoding(self): class MultiPathServerTestCase(BaseServerTestCase): threadFunc = staticmethod(http_multi_server) request_count = 2 - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_path1(self): p = xmlrpclib.ServerProxy(URL+"/foo") self.assertEqual(p.pow(6,8), 6**8) self.assertRaises(xmlrpclib.Fault, p.add, 6, 8) - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_path2(self): p = xmlrpclib.ServerProxy(URL+"/foo/bar") self.assertEqual(p.add(6,8), 6+8) self.assertRaises(xmlrpclib.Fault, p.pow, 6, 8) - # TODO: RUSTPYTHON - @unittest.expectedFailure + @support.requires_resource('walltime') def test_path3(self): p = xmlrpclib.ServerProxy(URL+"/is/broken") self.assertRaises(xmlrpclib.Fault, p.add, 6, 8) - # TODO: RUSTPYTHON - @unittest.expectedFailure + @support.requires_resource('walltime') def test_invalid_path(self): p = xmlrpclib.ServerProxy(URL+"/invalid") self.assertRaises(xmlrpclib.Fault, p.add, 6, 8) - # TODO: RUSTPYTHON - @unittest.expectedFailure + @support.requires_resource('walltime') def test_path_query_fragment(self): p = xmlrpclib.ServerProxy(URL+"/foo?k=v#frag") self.assertEqual(p.test(), "/foo?k=v#frag") - # TODO: RUSTPYTHON - @unittest.expectedFailure + @support.requires_resource('walltime') def test_path_fragment(self): p = xmlrpclib.ServerProxy(URL+"/foo#frag") self.assertEqual(p.test(), "/foo#frag") - # TODO: RUSTPYTHON - @unittest.expectedFailure + @support.requires_resource('walltime') def test_path_query(self): p = xmlrpclib.ServerProxy(URL+"/foo?k=v") self.assertEqual(p.test(), "/foo?k=v") - # TODO: RUSTPYTHON - @unittest.expectedFailure + @support.requires_resource('walltime') def test_empty_path(self): p = xmlrpclib.ServerProxy(URL) self.assertEqual(p.test(), "/RPC2") - # TODO: RUSTPYTHON - @unittest.expectedFailure + @support.requires_resource('walltime') def test_root_path(self): p = xmlrpclib.ServerProxy(URL + "/") self.assertEqual(p.test(), "/") - # TODO: RUSTPYTHON - @unittest.expectedFailure + @support.requires_resource('walltime') def test_empty_path_query(self): p = xmlrpclib.ServerProxy(URL + "?k=v") self.assertEqual(p.test(), "?k=v") - # TODO: RUSTPYTHON - @unittest.expectedFailure + @support.requires_resource('walltime') def test_empty_path_fragment(self): p = xmlrpclib.ServerProxy(URL + "#frag") self.assertEqual(p.test(), "#frag") @@ -1163,8 +1104,6 @@ def setUp(self): #A test case that verifies that a server using the HTTP/1.1 keep-alive mechanism #does indeed serve subsequent requests on the same connection class KeepaliveServerTestCase1(BaseKeepaliveServerTestCase): - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_two(self): p = xmlrpclib.ServerProxy(URL) #do three requests. @@ -1181,13 +1120,14 @@ def test_two(self): self.assertGreaterEqual(len(self.RequestHandler.myRequests[-1]), 2) -@unittest.skip("TODO: RUSTPYTHON, appears to hang") #test special attribute access on the serverproxy, through the __call__ #function. class KeepaliveServerTestCase2(BaseKeepaliveServerTestCase): #ask for two keepalive requests to be handled. request_count=2 + # TODO: RUSTPYTHON + @unittest.skip("test not hangs RUSTPYTHON") def test_close(self): p = xmlrpclib.ServerProxy(URL) #do some requests with close. @@ -1248,8 +1188,6 @@ def send_content(self, connection, body): def setUp(self): BaseServerTestCase.setUp(self) - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_gzip_request(self): t = self.Transport() t.encode_threshold = None @@ -1273,8 +1211,6 @@ def test_bad_gzip_request(self): p.pow(6, 8) p("close")() - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_gzip_response(self): t = self.Transport() p = xmlrpclib.ServerProxy(URL, transport=t) @@ -1333,8 +1269,6 @@ def assertContainsAdditionalHeaders(self, headers, additional): for key, value in additional.items(): self.assertEqual(headers.get(key), value) - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_header(self): p = xmlrpclib.ServerProxy(URL, headers=[('X-Test', 'foo')]) self.assertEqual(p.pow(6, 8), 6**8) @@ -1342,8 +1276,6 @@ def test_header(self): headers = self.RequestHandler.test_headers self.assertContainsAdditionalHeaders(headers, {'X-Test': 'foo'}) - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_header_many(self): p = xmlrpclib.ServerProxy( URL, headers=[('X-Test', 'foo'), ('X-Test-Second', 'bar')]) @@ -1353,8 +1285,6 @@ def test_header_many(self): self.assertContainsAdditionalHeaders( headers, {'X-Test': 'foo', 'X-Test-Second': 'bar'}) - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_header_empty(self): p = xmlrpclib.ServerProxy(URL, headers=[]) self.assertEqual(p.pow(6, 8), 6**8) @@ -1362,8 +1292,6 @@ def test_header_empty(self): headers = self.RequestHandler.test_headers self.assertContainsAdditionalHeaders(headers, {}) - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_header_tuple(self): p = xmlrpclib.ServerProxy(URL, headers=(('X-Test', 'foo'),)) self.assertEqual(p.pow(6, 8), 6**8) @@ -1371,8 +1299,6 @@ def test_header_tuple(self): headers = self.RequestHandler.test_headers self.assertContainsAdditionalHeaders(headers, {'X-Test': 'foo'}) - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_header_items(self): p = xmlrpclib.ServerProxy(URL, headers={'X-Test': 'foo'}.items()) self.assertEqual(p.pow(6, 8), 6**8) @@ -1431,8 +1357,6 @@ def tearDown(self): default_class = http.client.HTTPMessage xmlrpc.server.SimpleXMLRPCRequestHandler.MessageClass = default_class - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_basic(self): # check that flag is false by default flagval = xmlrpc.server.SimpleXMLRPCServer._send_traceback_header @@ -1527,8 +1451,6 @@ def test_cgi_get(self): self.assertEqual(message, 'Bad Request') - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_cgi_xmlrpc_response(self): data = """ @@ -1545,8 +1467,8 @@ def test_cgi_xmlrpc_response(self): """ with os_helper.EnvironmentVarGuard() as env, \ - captured_stdout(encoding=self.cgi.encoding) as data_out, \ - support.captured_stdin() as data_in: + captured_stdout(encoding=self.cgi.encoding) as data_out, \ + support.captured_stdin() as data_in: data_in.write(data) data_in.seek(0) env['CONTENT_LENGTH'] = str(len(data)) @@ -1574,8 +1496,6 @@ def test_cgi_xmlrpc_response(self): class UseBuiltinTypesTestCase(unittest.TestCase): - # TODO: RUSTPYTHON - @unittest.expectedFailure def test_use_builtin_types(self): # SimpleXMLRPCDispatcher.__init__ accepts use_builtin_types, which # makes all dispatch of binary data as bytes instances, and all @@ -1602,7 +1522,7 @@ def test_cgihandler_has_use_builtin_types_flag(self): def test_xmlrpcserver_has_use_builtin_types_flag(self): server = xmlrpc.server.SimpleXMLRPCServer(("localhost", 0), - use_builtin_types=True) + use_builtin_types=True) server.server_close() self.assertTrue(server.use_builtin_types) diff --git a/Lib/xmlrpc/client.py b/Lib/xmlrpc/client.py index 121e44023c..b96f45e905 100644 --- a/Lib/xmlrpc/client.py +++ b/Lib/xmlrpc/client.py @@ -135,8 +135,7 @@ from decimal import Decimal import http.client import urllib.parse -# XXX RUSTPYTHON TODO: pyexpat -# from xml.parsers import expat +from xml.parsers import expat import errno from io import BytesIO try: @@ -209,9 +208,9 @@ def __init__(self, url, errcode, errmsg, headers): self.headers = headers def __repr__(self): return ( - "<%s for %s: %s %s>" % - (self.__class__.__name__, self.url, self.errcode, self.errmsg) - ) + "<%s for %s: %s %s>" % + (self.__class__.__name__, self.url, self.errcode, self.errmsg) + ) ## # Indicates a broken XML-RPC response package. This exception is @@ -851,9 +850,9 @@ def __init__(self, results): def __getitem__(self, i): item = self.results[i] - if type(item) == type({}): + if isinstance(item, dict): raise Fault(item['faultCode'], item['faultString']) - elif type(item) == type([]): + elif isinstance(item, list): return item[0] else: raise ValueError("unexpected type in multicall result") @@ -995,7 +994,7 @@ def dumps(params, methodname=None, methodresponse=None, encoding=None, "", methodname, "\n", data, "\n" - ) + ) elif methodresponse: # a method response, or a fault structure data = ( @@ -1003,7 +1002,7 @@ def dumps(params, methodname=None, methodresponse=None, encoding=None, "\n", data, "\n" - ) + ) else: return data # return as is return "".join(data) @@ -1198,7 +1197,7 @@ def single_request(self, host, handler, request_body, verbose=False): host + handler, resp.status, resp.reason, dict(resp.getheaders()) - ) + ) ## @@ -1235,7 +1234,7 @@ def get_host_info(self, host): auth = "".join(auth.split()) # get rid of whitespace extra_headers = [ ("Authorization", "Basic " + auth) - ] + ] else: extra_headers = [] @@ -1313,8 +1312,8 @@ def send_headers(self, connection, headers): def send_content(self, connection, request_body): #optionally encode the request if (self.encode_threshold is not None and - self.encode_threshold < len(request_body) and - gzip): + self.encode_threshold < len(request_body) and + gzip): connection.putheader("Content-Encoding", "gzip") request_body = gzip_encode(request_body) @@ -1340,10 +1339,7 @@ def parse_response(self, response): p, u = self.getparser() - while 1: - data = stream.read(1024) - if not data: - break + while data := stream.read(1024): if self.verbose: print("body:", repr(data)) p.feed(data) @@ -1375,12 +1371,12 @@ def make_connection(self, host): if not hasattr(http.client, "HTTPSConnection"): raise NotImplementedError( - "your version of http.client doesn't support HTTPS") + "your version of http.client doesn't support HTTPS") # create a HTTPS connection object from a host descriptor # host may be a string, or a (host, x509-dict) tuple chost, self._extra_headers, x509 = self.get_host_info(host) self._connection = host, http.client.HTTPSConnection(chost, - None, context=self.context, **(x509 or {})) + None, context=self.context, **(x509 or {})) return self._connection[1] ## @@ -1467,7 +1463,7 @@ def __request(self, methodname, params): self.__handler, request, verbose=self.__verbose - ) + ) if len(response) == 1: response = response[0] @@ -1476,9 +1472,9 @@ def __request(self, methodname, params): def __repr__(self): return ( - "<%s for %s%s>" % - (self.__class__.__name__, self.__host, self.__handler) - ) + "<%s for %s%s>" % + (self.__class__.__name__, self.__host, self.__handler) + ) def __getattr__(self, name): # magic method dispatcher diff --git a/Lib/xmlrpc/server.py b/Lib/xmlrpc/server.py index 69a260f5b1..c8fd8d6f46 100644 --- a/Lib/xmlrpc/server.py +++ b/Lib/xmlrpc/server.py @@ -140,7 +140,7 @@ def resolve_dotted_attribute(obj, attr, allow_dotted_names=True): if i.startswith('_'): raise AttributeError( 'attempt to access private attribute "%s"' % i - ) + ) else: obj = getattr(obj,i) return obj @@ -150,8 +150,8 @@ def list_public_methods(obj): object, which represent callable attributes""" return [member for member in dir(obj) - if not member.startswith('_') and - callable(getattr(obj, member))] + if not member.startswith('_') and + callable(getattr(obj, member))] class SimpleXMLRPCDispatcher: """Mix-in class that dispatches XML-RPC requests. @@ -230,8 +230,8 @@ def register_introspection_functions(self): """ self.funcs.update({'system.listMethods' : self.system_listMethods, - 'system.methodSignature' : self.system_methodSignature, - 'system.methodHelp' : self.system_methodHelp}) + 'system.methodSignature' : self.system_methodSignature, + 'system.methodHelp' : self.system_methodHelp}) def register_multicall_functions(self): """Registers the XML-RPC multicall method in the system @@ -268,17 +268,11 @@ def _marshaled_dispatch(self, data, dispatch_method = None, path = None): except Fault as fault: response = dumps(fault, allow_none=self.allow_none, encoding=self.encoding) - except: - # report exception back to server - exc_type, exc_value, exc_tb = sys.exc_info() - try: - response = dumps( - Fault(1, "%s:%s" % (exc_type, exc_value)), - encoding=self.encoding, allow_none=self.allow_none, - ) - finally: - # Break reference cycle - exc_type = exc_value = exc_tb = None + except BaseException as exc: + response = dumps( + Fault(1, "%s:%s" % (type(exc), exc)), + encoding=self.encoding, allow_none=self.allow_none, + ) return response.encode(self.encoding, 'xmlcharrefreplace') @@ -330,10 +324,10 @@ def system_methodHelp(self, method_name): elif not hasattr(self.instance, '_dispatch'): try: method = resolve_dotted_attribute( - self.instance, - method_name, - self.allow_dotted_names - ) + self.instance, + method_name, + self.allow_dotted_names + ) except AttributeError: pass @@ -367,17 +361,12 @@ def system_multicall(self, call_list): results.append( {'faultCode' : fault.faultCode, 'faultString' : fault.faultString} - ) - except: - exc_type, exc_value, exc_tb = sys.exc_info() - try: - results.append( - {'faultCode' : 1, - 'faultString' : "%s:%s" % (exc_type, exc_value)} - ) - finally: - # Break reference cycle - exc_type = exc_value = exc_tb = None + ) + except BaseException as exc: + results.append( + {'faultCode' : 1, + 'faultString' : "%s:%s" % (type(exc), exc)} + ) return results def _dispatch(self, method, params): @@ -440,7 +429,7 @@ class SimpleXMLRPCRequestHandler(BaseHTTPRequestHandler): # Class attribute listing the accessible path components; # paths not on this list will result in a 404 error. - rpc_paths = ('/', '/RPC2') + rpc_paths = ('/', '/RPC2', '/pydoc.css') #if not None, encode responses larger than this, if possible encode_threshold = 1400 #a common MTU @@ -513,8 +502,8 @@ def do_POST(self): # check to see if a subclass implements _dispatch and dispatch # using that method if present. response = self.server._marshaled_dispatch( - data, getattr(self, '_dispatch', None), self.path - ) + data, getattr(self, '_dispatch', None), self.path + ) except Exception as e: # This should only happen if the module is buggy # internal error, report as HTTP server error self.send_response(500) @@ -563,7 +552,7 @@ def decode_request_content(self, data): self.end_headers() def report_404 (self): - # Report a 404 error + # Report a 404 error self.send_response(404) response = b'No such page' self.send_header("Content-type", "text/plain") @@ -633,20 +622,15 @@ def get_dispatcher(self, path): def _marshaled_dispatch(self, data, dispatch_method = None, path = None): try: response = self.dispatchers[path]._marshaled_dispatch( - data, dispatch_method, path) - except: + data, dispatch_method, path) + except BaseException as exc: # report low level exception back to server # (each dispatcher should have handled their own # exceptions) - exc_type, exc_value = sys.exc_info()[:2] - try: - response = dumps( - Fault(1, "%s:%s" % (exc_type, exc_value)), - encoding=self.encoding, allow_none=self.allow_none) - response = response.encode(self.encoding, 'xmlcharrefreplace') - finally: - # Break reference cycle - exc_type = exc_value = None + response = dumps( + Fault(1, "%s:%s" % (type(exc), exc)), + encoding=self.encoding, allow_none=self.allow_none) + response = response.encode(self.encoding, 'xmlcharrefreplace') return response class CGIXMLRPCRequestHandler(SimpleXMLRPCDispatcher): @@ -678,11 +662,11 @@ def handle_get(self): message, explain = BaseHTTPRequestHandler.responses[code] response = http.server.DEFAULT_ERROR_MESSAGE % \ - { - 'code' : code, - 'message' : message, - 'explain' : explain - } + { + 'code' : code, + 'message' : message, + 'explain' : explain + } response = response.encode('utf-8') print('Status: %d %s' % (code, message)) print('Content-Type: %s' % http.server.DEFAULT_ERROR_CONTENT_TYPE) @@ -701,7 +685,7 @@ def handle_request(self, request_text=None): """ if request_text is None and \ - os.environ.get('REQUEST_METHOD', None) == 'GET': + os.environ.get('REQUEST_METHOD', None) == 'GET': self.handle_get() else: # POST data is normally available through stdin @@ -733,12 +717,10 @@ def markup(self, text, escape=None, funcs={}, classes={}, methods={}): # names. Only methods with names consisting of word characters # and '.'s are hyperlinked. pattern = re.compile(r'\b((http|https|ftp)://\S+[\w/]|' - r'RFC[- ]?(\d+)|' - r'PEP[- ]?(\d+)|' - r'(self\.)?((?:\w|\.)+))\b') - while 1: - match = pattern.search(text, here) - if not match: break + r'RFC[- ]?(\d+)|' + r'PEP[- ]?(\d+)|' + r'(self\.)?((?:\w|\.)+))\b') + while match := pattern.search(text, here): start, end = match.span() results.append(escape(text[here:start])) @@ -747,10 +729,10 @@ def markup(self, text, escape=None, funcs={}, classes={}, methods={}): url = escape(all).replace('"', '"') results.append('%s' % (url, url)) elif rfc: - url = 'http://www.rfc-editor.org/rfc/rfc%d.txt' % int(rfc) + url = 'https://www.rfc-editor.org/rfc/rfc%d.txt' % int(rfc) results.append('%s' % (url, escape(all))) elif pep: - url = 'https://www.python.org/dev/peps/pep-%04d/' % int(pep) + url = 'https://peps.python.org/pep-%04d/' % int(pep) results.append('%s' % (url, escape(all))) elif text[end:end+1] == '(': results.append(self.namelink(name, methods, funcs, classes)) @@ -784,7 +766,7 @@ def docroutine(self, object, name, mod=None, docstring = pydoc.getdoc(object) decl = title + argspec + (note and self.grey( - '%s' % note)) + '%s' % note)) doc = self.markup( docstring, self.preformat, funcs, classes, methods) @@ -801,7 +783,7 @@ def docserver(self, server_name, package_documentation, methods): server_name = self.escape(server_name) head = '%s' % server_name - result = self.heading(head, '#ffffff', '#7799ee') + result = self.heading(head) doc = self.markup(package_documentation, self.preformat, fdict) doc = doc and '%s' % doc @@ -812,10 +794,25 @@ def docserver(self, server_name, package_documentation, methods): for key, value in method_items: contents.append(self.docroutine(value, key, funcs=fdict)) result = result + self.bigsection( - 'Methods', '#ffffff', '#eeaa77', ''.join(contents)) + 'Methods', 'functions', ''.join(contents)) return result + + def page(self, title, contents): + """Format an HTML page.""" + css_path = "/pydoc.css" + css_link = ( + '' % + css_path) + return '''\ + + + + +Codestin Search App +%s%s''' % (title, css_link, contents) + class XMLRPCDocGenerator: """Generates documentation for an XML-RPC server. @@ -827,7 +824,7 @@ def __init__(self): # setup variables used for HTML documentation self.server_name = 'XML-RPC Server Documentation' self.server_documentation = \ - "This server exports the following methods through the XML-RPC "\ + "This server exports the following methods through the XML-RPC " \ "protocol." self.server_title = 'XML-RPC Server Documentation' @@ -875,25 +872,25 @@ def generate_html_documentation(self): elif not hasattr(self.instance, '_dispatch'): try: method = resolve_dotted_attribute( - self.instance, - method_name - ) + self.instance, + method_name + ) except AttributeError: method = method_info else: method = method_info else: - assert 0, "Could not find method in self.functions and no "\ + assert 0, "Could not find method in self.functions and no " \ "instance installed" methods[method_name] = method documenter = ServerHTMLDoc() documentation = documenter.docserver( - self.server_name, - self.server_documentation, - methods - ) + self.server_name, + self.server_documentation, + methods + ) return documenter.page(html.escape(self.server_title), documentation) @@ -907,6 +904,12 @@ class DocXMLRPCRequestHandler(SimpleXMLRPCRequestHandler): for documentation. """ + def _get_css(self, url): + path_here = os.path.dirname(os.path.realpath(__file__)) + css_path = os.path.join(path_here, "..", "pydoc_data", "_pydoc.css") + with open(css_path, mode="rb") as fp: + return fp.read() + def do_GET(self): """Handles the HTTP GET request. @@ -918,9 +921,15 @@ def do_GET(self): self.report_404() return - response = self.server.generate_html_documentation().encode('utf-8') + if self.path.endswith('.css'): + content_type = 'text/css' + response = self._get_css(self.path) + else: + content_type = 'text/html' + response = self.server.generate_html_documentation().encode('utf-8') + self.send_response(200) - self.send_header("Content-type", "text/html") + self.send_header('Content-Type', '%s; charset=UTF-8' % content_type) self.send_header("Content-length", str(len(response))) self.end_headers() self.wfile.write(response) diff --git a/stdlib/src/zlib.rs b/stdlib/src/zlib.rs index 83a7535c33..9f14422d77 100644 --- a/stdlib/src/zlib.rs +++ b/stdlib/src/zlib.rs @@ -53,6 +53,8 @@ mod zlib { #[pyattr] const MAX_WBITS: i8 = 15; #[pyattr] + const WBITS: i8 = MAX_WBITS; + #[pyattr] const DEF_BUF_SIZE: usize = 16 * 1024; #[pyattr] const DEF_MEM_LEVEL: u8 = 8; @@ -596,17 +598,30 @@ mod zlib { decompress: PyMutex, unused_data: PyMutex, unconsumed_tail: PyMutex, + eof: AtomicCell, + needs_input: AtomicCell, + available_in_real: AtomicCell + } + + #[derive(FromArgs)] + pub struct PyZlibDecompressorArgs { + #[pyarg(any, default = "ArgPrimitiveIndex { value: MAX_WBITS }")] + pub wbits: ArgPrimitiveIndex, } impl Constructor for ZlibDecompressor { - type Args = (); + type Args = PyZlibDecompressorArgs; - fn py_new(cls: PyTypeRef, _args: Self::Args, vm: &VirtualMachine) -> PyResult { - let decompress = Decompress::new(true); + fn py_new(cls: PyTypeRef, args: Self::Args, vm: &VirtualMachine) -> PyResult { + // TODO: use args + let decompress = InitOptions::new(args.wbits.value, vm)?.decompress(); let zlib_decompressor = Self { decompress: PyMutex::new(decompress), unused_data: PyMutex::new(PyBytes::from(vec![]).into_ref(&vm.ctx)), unconsumed_tail: PyMutex::new(PyBytes::from(vec![]).into_ref(&vm.ctx)), + eof: AtomicCell::new(false), + needs_input: AtomicCell::new(true), + available_in_real: AtomicCell::new(0) }; zlib_decompressor .into_ref_with_type(vm, cls) @@ -616,6 +631,11 @@ mod zlib { #[pyclass(with(Constructor))] impl ZlibDecompressor { + #[pygetset] + fn needs_input(&self) -> bool { + self.needs_input.load() + } + #[pygetset] fn unused_data(&self) -> PyBytesRef { self.unused_data.lock().clone() @@ -626,6 +646,11 @@ mod zlib { self.unconsumed_tail.lock().clone() } + #[pygetset] + fn eof(&self) -> bool { + self.eof.load() + } + fn save_unused_input( &self, d: &Decompress, @@ -649,25 +674,38 @@ mod zlib { } #[pymethod] - fn decompress(&self, args: PyBytesRef, vm: &VirtualMachine) -> PyResult> { - // let max_length = args.max_length.value; - // let max_length = (max_length != 0).then_some(max_length); - let max_length = None; - let data = args.as_bytes(); + fn decompress(&self, args: DecompressArgs, vm: &VirtualMachine) -> PyResult> { + let max_length = args.max_length.value; + let max_length = (max_length != 0).then_some(max_length); + let data = args.data.borrow_buf(); + self.available_in_real.store(data.len() as i32); let mut d = self.decompress.lock(); let orig_in = d.total_in(); let (ret, stream_end) = - match _decompress(data, &mut d, DEF_BUF_SIZE, max_length, false, vm) { + match _decompress(&data, &mut d, DEF_BUF_SIZE, max_length, false, vm) { Ok((buf, true)) => { - // Eof is true + self.eof.store(true); + self.needs_input.store(false); + // if self.available_in_real.load() > 0 { + // // PyObject *unused_data = PyBytes_FromStringAndSize( + // // (char *)self->zst.next_in, self->avail_in_real); + // *self.unused_data.lock() = todo!(); + // } (Ok(buf), true) } - Ok((buf, false)) => (Ok(buf), false), + Ok((buf, false)) => { + if self.available_in_real.load() == 0 { + self.needs_input.store(true); + } else { + self.needs_input.store(false); + } + (Ok(buf), false) + }, Err(err) => (Err(err), false), }; - self.save_unused_input(&d, data, stream_end, orig_in, vm); + self.save_unused_input(&d, &data, stream_end, orig_in, vm); let leftover = if stream_end { b""