Mypy intentionally does not check annotations inside untyped `def` statements. This is a feature meant to make it easier to gradually introduce types in code th

Mypy intentionally does not check annotations inside untyped `def` statements. This is a feature meant to make it easier to gradually introduce types in code that wasn't intended to be typechecked. If you call mypy with the flag `--check-untyped-defs` or just annotate the function with anything at all, you will see mypy checks the inside of the function: from typing import Any def blah() -> Any: ... I'm not sure what you mean by "there's not really such a thing as static analysis" in Python -- that's exactly what Mypy does.