[Zope-dev] Hotfixes and __bases__

In Caseman's How-To named "Extend Zope Dynamically with Hotfixes", at http://www.zope.org/Members/Caseman/Dynamic_Hotfix, he mentions that you could: "Add new base classes to existing classes". I have tried this, and can't get it to work, my question is: is it possible?, and if so, how do I make it work? :) I am using Python 1.5.2, which supports dynamically updating the __bases__ attribute. I can successfully update the bases in simple Python classes, but when I try to do it to a Zope (2.3.2) class (specifically Folder), my assignment to the __bases__ attribute doesn't update it. Is what I'm doing even possible? thanks -d