- Add `typing_extensions.get_annotations`, a backport of

`inspect.get_annotations` that adds features specified

by PEP 649. Patch by Jelle Zijlstra.

.. function:: get_annotations(obj, *, globals=None, locals=None, eval_str=False, format=Format.VALUE)

See :py:func:`inspect.get_annotations`. In the standard library since Python 3.10.

``typing_extensions`` adds the keyword argument ``format``, as specified

by :pep:`649`. The supported formats are listed in the :class:`Format` enum.

The default format, :attr:`Format.VALUE`, behaves the same across all versions.

For the other two formats, ``typing_extensions`` provides a rough approximation

of the :pep:`649` behavior on versions of Python that do not support it.

The purpose of this backport is to allow users who would like to use

:attr:`Format.FORWARDREF` or :attr:`Format.SOURCE` semantics once

:pep:`649` is implemented, but who also

want to support earlier Python versions, to simply write::

.. versionadded:: 4.13.0

Enums

.. class:: Format

The formats for evaluating annotations introduced by :pep:`649`.

Members of this enum can be passed as the *format* argument

to :func:`get_annotations`.

The final place of this enum in the standard library has not yet

been determined (see :pep:`649` and :pep:`749`), but the names

and integer values are stable and will continue to work.

.. attribute:: VALUE

Equal to 1. The default value. The function will return the conventional Python values

for the annotations. This format is identical to the return value for

the function under earlier versions of Python.

.. attribute:: FORWARDREF

Equal to 2. When :pep:`649` is implemented, this format will attempt to return the

conventional Python values for the annotations. However, if it encounters

an undefined name, it dynamically creates a proxy object (a ForwardRef)

that substitutes for that value in the expression.

``typing_extensions`` emulates this value on versions of Python which do

not support :pep:`649` by returning the same value as for ``VALUE`` semantics.

.. attribute:: SOURCE

Equal to 3. When :pep:`649` is implemented, this format will produce an annotation

dictionary where the values have been replaced by strings containing

an approximation of the original source code for the annotation expressions.

``typing_extensions`` emulates this by evaluating the annotations using

``VALUE`` semantics and then stringifying the results.

.. versionadded:: 4.13.0