Iterate over subclasses of a given class in a given module

Question

In Python, given a module X and a class Y, how can I iterate or generate a list of all subclasses of Y that exist in module X?

Answer 1

Given the module foo.py

class foo(object): pass
class bar(foo): pass
class baz(foo): pass

class grar(Exception): pass

def find_subclasses(module, clazz):
    for name in dir(module):
        o = getattr(module, name)

        try: 
             if issubclass(o, clazz):
             yield name, o
        except TypeError: pass

>>> import foo
>>> list(foo.find_subclasses(foo, foo.foo))
[('bar', ), ('baz', ), ('foo', )]
>>> list(foo.find_subclasses(foo, object))
[('bar', ), ('baz', ), ('foo', ), ('grar', )]
>>> list(foo.find_subclasses(foo, Exception))
[('grar', )]