I just released typing-extensions 4.6.0: https://pypi.org/project/typing-extensions/4.6.0/ This release comes with documentation at https://typing-extensions.readthedocs.io/en/latest/ (previously typing-extensions was documented only through its README). In addition, there is a large number of additions and improvements. Copying from the changelog: - `typing_extensions` is now documented at https://typing-extensions.readthedocs.io/en/latest/. Patch by Jelle Zijlstra. - Add `typing_extensions.Buffer`, a marker class for buffer types, as proposed by PEP 688. Equivalent to `collections.abc.Buffer` in Python 3.12. Patch by Jelle Zijlstra. - Backport two CPython PRs fixing various issues with `typing.Literal`: https://github.com/python/cpython/pull/23294 and https://github.com/python/cpython/pull/23383. Both CPython PRs were originally by Yurii Karabas, and both were backported to Python >=3.9.1, but no earlier. Patch by Alex Waygood. A side effect of one of the changes is that equality comparisons of `Literal` objects will now raise a `TypeError` if one of the `Literal` objects being compared has a mutable parameter. (Using mutable parameters with `Literal` is not supported by PEP 586 or by any major static type checkers.) - `Literal` is now reimplemented on all Python versions <= 3.10.0. The `typing_extensions` version does not suffer from the bug that was fixed in https://github.com/python/cpython/pull/29334. (The CPython bugfix was backported to CPython 3.10.1 and 3.9.8, but no earlier.) - Backport [CPython PR 26067](https://github.com/python/cpython/pull/26067) (originally by Yurii Karabas), ensuring that `isinstance()` calls on protocols raise `TypeError` when the protocol is not decorated with `@runtime_checkable`. Patch by Alex Waygood. - Backport several significant performance improvements to runtime-checkable protocols that have been made in Python 3.12 (see https://github.com/python/cpython/issues/74690 for details). Patch by Alex Waygood. A side effect of one of the performance improvements is that the members of a runtime-checkable protocol are now considered “frozen” at runtime as soon as the class has been created. Monkey-patching attributes onto a runtime-checkable protocol will still work, but will have no impact on `isinstance()` checks comparing objects to the protocol. See ["What's New in Python 3.12"]( https://docs.python.org/3.12/whatsnew/3.12.html#typing) for more details. - `isinstance()` checks against runtime-checkable protocols now use `inspect.getattr_static()` rather than `hasattr()` to lookup whether attributes exist (backporting https://github.com/python/cpython/pull/103034). This means that descriptors and `__getattr__` methods are no longer unexpectedly evaluated during `isinstance()` checks against runtime-checkable protocols. However, it may also mean that some objects which used to be considered instances of a runtime-checkable protocol on older versions of `typing_extensions` may no longer be considered instances of that protocol using the new release, and vice versa. Most users are unlikely to be affected by this change. Patch by Alex Waygood. - Backport the ability to define `__init__` methods on Protocol classes, a change made in Python 3.11 (originally implemented in https://github.com/python/cpython/pull/31628 by Adrian Garcia Badaracco). Patch by Alex Waygood. - Speedup `isinstance(3, typing_extensions.SupportsIndex)` by >10x on Python <3.12. Patch by Alex Waygood. - Add `typing_extensions` versions of `SupportsInt`, `SupportsFloat`, `SupportsComplex`, `SupportsBytes`, `SupportsAbs` and `SupportsRound`. These have the same semantics as the versions from the `typing` module, but `isinstance()` checks against the `typing_extensions` versions are >10x faster at runtime on Python <3.12. Patch by Alex Waygood. - Add `__orig_bases__` to non-generic TypedDicts, call-based TypedDicts, and call-based NamedTuples. Other TypedDicts and NamedTuples already had the attribute. Patch by Adrian Garcia Badaracco. - Add `typing_extensions.get_original_bases`, a backport of [`types.get_original_bases`]( https://docs.python.org/3.12/library/types.html#types.get_original_bases), introduced in Python 3.12 (CPython PR https://github.com/python/cpython/pull/101827, originally by James Hilton-Balfe). Patch by Alex Waygood. This function should always produce correct results when called on classes constructed using features from `typing_extensions`. However, it may produce incorrect results when called on some `NamedTuple` or `TypedDict` classes that use `typing.{NamedTuple,TypedDict}` on Python <=3.11. - Constructing a call-based `TypedDict` using keyword arguments for the fields now causes a `DeprecationWarning` to be emitted. This matches the behaviour of `typing.TypedDict` on 3.11 and 3.12. - Backport the implementation of `NewType` from 3.10 (where it is implemented as a class rather than a function). This allows user-defined `NewType`s to be pickled. Patch by Alex Waygood. - Fix tests and import on Python 3.12, where `typing.TypeVar` can no longer be subclassed. Patch by Jelle Zijlstra. - Add `typing_extensions.TypeAliasType`, a backport of `typing.TypeAliasType` from PEP 695. Patch by Jelle Zijlstra. - Backport changes to the repr of `typing.Unpack` that were made in order to implement [PEP 692](https://peps.python.org/pep-0692/) (backport of https://github.com/python/cpython/pull/104048). Patch by Alex Waygood. Please report any issues at https://github.com/python/typing_extensions/issues.