Example of printing a warning for implicit overriding of functions

explicitoverride_meta.py

#!/usr/bin/env python3

import types


class ExplicitOverloadType(type):
    def __init__(self, name, bases, dict):
        for key, val in dict.items():
            if isinstance(val, types.FunctionType):
                if getattr(val, "_is_overriden", False):
                    continue

                for base in bases:
                    if hasattr(base, key):
                        print("Warning: {} is implicitly overridden".format(key))

        type.__init__(self, name, bases, dict)


def override(f):
    f._is_overriden = True
    return f


class Base(metaclass=ExplicitOverloadType):
    def foo(self):
        pass

    def bar(self):
        pass


class Child(Base):
    @override
    def foo(self):
        pass

    def bar(self):
        pass


if __name__ == '__main__':
    c = Child()

$ python3 metalearn.py
Warning: bar is implicitly overridden