Uhh... Did you not see my parenthetical reference to `__slots__`? See this SO post[1] for more details.
[1] - http://stackoverflow.com/questions/472000/python-slots
[1] - http://stackoverflow.com/questions/472000/python-slots
Though I'm not sure `__slots__` actually saves any time, as it's really a space optimization. I've tried it before for hot code and even seen very slight (probably not significant) slowdowns.