newb: object factory, and iteration

[Jeremy Yallop]

Chris wrote:
> But is there a way for me to list all instances of a certain
> class?  

I don't think there is, in general.  If, as in your example, you can
modify the __init__ method of the class, you could add weak references
to created instances to a class member list.  It would be even nicer,
though, to make a metaclass, instances of which maintain (weak)
references to instances of themselves.

Jeremy.