> Is there a simple way to get the *ordered* list of instance
Here's one way to do it (weather doing it is a good idea or not is debatable):
from operator import attrgetter
def __init__(self, a, b, c, d):
self.a, self.b, self.c, self.d = a, b, c, d
get = attrgetter('a', 'b', 'c', 'd')
self.state = lambda: get(self)