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

Can I suggest that neither of the answers from Chris AtLee and zacherates fulfill the requirements? I think this modification to zacerates answer is better:

def find_subclasses(module, clazz):
    for name in dir(module):
        o = getattr(module, name)
        try:
            if (o != clazz) and issubclass(o, clazz):
                yield name, o
        except TypeError: pass

The reason I disagree with the given answers is that the first does not produce classes that are a distant subclass of the given class, and the second includes the given class.