Shared via mypy Playground

main.py

from typing import final, assert_never, reveal_type

class Types:

    @final
    class A:
        pass

    @final
    class B:
        pass

def pprint(cls: type[Types.A | Types.B]) -> None:
    match cls:
        case Types.A:
            print("A")
            reveal_type(cls)
        case Types.B:
            print("B")
            reveal_type(cls)
        case _:
            reveal_type(cls)
            assert_never(cls)