The typing_extensions module serves two related purposes:
- Enable use of new type system features on older Python versions. For example,
typing.TypeGuard is new in Python 3.10, but typing_extensions allows users on
previous Python versions to use it too.
- Enable experimentation with new type system PEPs before they are accepted and
added to the typing module.
typing_extensions is treated specially by static type checkers such as mypy and
pyright. Objects defined in typing_extensions are treated the same way as
equivalent forms in typing.
