gistfile1.txt

import a


class B(a.A):
    pass


def itersubclasses(cls, _seen=None):
    """Generator over all subclasses of a given class in depth first order."""

    _seen = _seen or set()
    subs = cls.__subclasses__()
    for sub in subs:
        if sub not in _seen:
            _seen.add(sub)
            yield sub
            for sub in itersubclasses(sub, _seen):
                yield sub



print list(itersubclasses(a.A))


import other_thing


print list(itersubclasses(a.A))