[mfgs]

It already can be used for development, IDEs such as PyCharm perform quite effective live type checking based on type hints.

[Jasper_]

Note that PyCharm and mypy's semantics differ in some key ways:

https://youtrack.jetbrains.com/issue/PY-54411/Type-checkers-....

https://youtrack.jetbrains.com/issue/PY-24834/Support-strict...