import typing

class FinalException(Exception):
    pass

class Final:
    def __init_subclass__(cls, **kwargs) -> None:
        for base in cls.__bases__:
            if base is not Final and issubclass(base, Final):
                raise FinalException(base)
        super().__init_subclass__(**kwargs)

def check_final(cls):
    try:
        class Subclass(cls):
            pass
    except FinalException:
        pass
    else:
        raise Exception('Should raise')

class NonGenericFinal(Final):
    pass

check_final(NonGenericFinal)

T = typing.TypeVar('T')

class GenericFinal(typing.Generic[T], Final):
    pass

check_final(GenericFinal)