The:mod:`typing` module incorporates several new features:

* Protocol definitions. See:pep:`544`,:class:`typing.Protocol` and

:func:`typing.runtime_checkable`. Simple ABCs like

:class:`typing.SupportsInt` are now ``Protocol`` subclasses.

* A dictionary type with per-key types. See:pep:`589` and

:class:`typing.TypedDict`.

TypedDict uses only string keys. By default, every key is required

to be present. Specify "total=False" to allow keys to be optional::

* Literal types. See:pep:`586` and:class:`typing.Literal`.

Literal types indicate that a parameter or return value

is constrained to one or more specific literal values::

* "Final" variables, functions, methods and classes. See:pep:`591`,

:class:`typing.Final` and:func:`typing.final`.

The final qualifier instructs a static type checker to restrict

subclassing, overriding, or reassignment::

* Protocol definitions. See:pep:`544`,:class:`typing.Protocol` and

:func:`typing.runtime_checkable`. Simple ABCs like

:class:`typing.SupportsInt` are now ``Protocol`` subclasses.

* New protocol class:class:`typing.SupportsIndex`.

terminate the current thread if called while the interpreter is

finalizing, making them consistent with:c:func:`PyEval_RestoreThread`,

:c:func:`Py_END_ALLOW_THREADS`, and:c:func:`PyGILState_Ensure`. If this

behaviour is not desired, guard the call by checking:c:func:`_Py_IsFinalizing`

behavior is not desired, guard the call by checking:c:func:`_Py_IsFinalizing`

or:c:func:`sys.is_finalizing`.

Changes in the Python API