python/typing_extensions

Typing Extensions

Documentation – PyPI

Overview

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.

typing_extensions uses Semantic Versioning. The major version will be incremented only for backwards-incompatible changes. Therefore, it's safe to depend on typing_extensions like this: typing_extensions ~=x.y, where x.y is the first version that includes all features you need. This is equivalent to typing_extensions >=x.y, <(x+1). Do not depend on ~= x.y.z unless you really know what you're doing; that defeats the purpose of semantic versioning.

Included items

See the documentation for a complete listing of module contents.

Contributing

See CONTRIBUTING.md for how to contribute to typing_extensions.