gistfile1.py

class Foo(object):
    def f(self, x=None):
        print 'hello'
        print x
        return None

class Bar(Foo):
    pass


def target(*args):
    return main, None

def main(args):
    b = Bar()
    b.f('fffuuu')
    x = Bar()
    x.f()
    return 0

if __name__ == '__main__':
    import sys
    main(sys.argv)