Can __iter__ be used as a classmethod?

Alex Martelli aleax at
Thu Mar 13 08:54:32 CET 2003

Aahz wrote:
>>    """Subclasses of Frozen are frozen, i.e. it is impossible to add
>>     new attributes to them and their instances, except via inheritance"""
> Why the heck didn't you use __slots__?!?!?!

Just using __slots__ (without a custom metaclass) would NOT "freeze" any
subclass: just by subclassing, you'd get instances to which attributes
could freely be added.

A custom metaclass might well be a more suitable approach, of course,
and it could, in particular. use __slots__ to optimize things.


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