class Bar(object):
def __init__(self, arg1=None, arg2=None, argN=None):
print arg1, arg2, argN
class Foo(Bar):
def __init__(self, my_new_arg=None, **kwds):
super(Foo, self).__init__(**kwds)
self.new_arg = my_new_arg
print my_new_arg
f = Foo(my_new_arg='x', arg2='y')