Hello again, everybody. Thank you very much for your responses. You guessed right, I didn't use the __hash__ method (and I forgot to mention that, sorry).
And unfortunately, I think I can't make them hashable, because the objects are compared based on their attributes, which are in turn other kind of objects compared based on other attributes. All these class instances are compared with __eq__/__ne__ and they wrap relatively complex data which would be hard to attempt to represent them unambiguously using a 32-bit integer. That's why I'm afraid I cannot use hashables. I guess I'll have to use something like the function of my first post. :( Thanks, - Gustavo. -- http://mail.python.org/mailman/listinfo/python-list