Add type annotations to your Python programs, and use mypy to type check them. Mypy is essentially a Python linter on steroids, and it can catch many programming errors by analyzing your program, without actually having to run it. Mypy has a powerful type system with features such as type inference, gradual typing, generics and union types.

The "mypy_extensions" module defines experimental extensions to the standard "typing" module that are supported by the mypy typechecker.

This package provides the modules for Python 3.