Mypy 0.991 released
8 Nov 2022: Mypy 0.991 was released. Read the blog post for the details. -Valentin Stanciu
Mypy 0.981 released
27 Sep 2022: Mypy 0.981 was released. Read the blog post for the details. -Jukka Lehtosalo and Jared Hance
Mypy 0.971 released
19 Jul 2022: Mypy 0.971 was released. Read the blog post for the details. -Jukka Lehtosalo and Ivan Levkivskyi
Mypy 0.960 released
25 May 2022: Mypy 0.960 was released. Read the blog post for the details. -Jukka Lehtosalo
def fib(n): a, b = 0, 1 while a < n: yield a a, b = b, a+b
def fib(n: int) -> Iterator[int]: a, b = 0, 1 while a < n: yield a a, b = b, a+b
Migrate existing code to static typing, a function at a time. You can freely mix static and dynamic typing within a program, within a module or within an expression. No need to give up dynamic typing — use static typing when it makes sense. Often just adding function signatures gives you statically typed code. Mypy can infer the types of other variables.
Mypy type checks programs that have type annotations conforming to PEP 484. Getting started is easy if you know Python. The aim is to support almost all Python language constructs in mypy.
Mypy has a powerful, modern type system with features such as bidirectional type inference, generics, callable types, abstract base classes, multiple inheritance and tuple types.
Many commonly used libraries have stubs (statically typed interface definitions) that allow mypy to check that your code uses the libraries correctly.