bpo-42194: Add "New in version: 3.9" to argparse.BooleanOptionalAction (GH-23026)

shangxiao · web-flow · commit da2e673c5397 · 2021-07-12T17:19:54.000+02:00
diff --git a/Doc/library/argparse.rst b/Doc/library/argparse.rst
@@ -853,6 +853,8 @@ is available in ``argparse`` and adds support for boolean actions such as
     >>> parser.parse_args(['--no-foo'])
     Namespace(foo=False)
 
+.. versionadded:: 3.9
+
 The recommended way to create a custom action is to extend :class:`Action`,
 overriding the ``__call__`` method and optionally the ``__init__`` and
 ``format_usage`` methods.
