I'm having the same problem described in: http://lists.zope.org/pipermail/zope-dev/1999-November/002427.html My class inherits from a few base classes including CatalogAware as a mixin; I'm trying to override a method in my core API superclass (which uses MySQLdb, and thus mx-DateTime), with a similar method that is compatible with Zope's DateTime; I got a TypeError that I think is due to ExtensionClass when trying to call the superclasses method, even with an instance of the subclass passed as the first variable. Since this didn't work, I ended up having to create a temporary instance of the superclass and inside a method of the subclass - not entirely graceful, but it works. Is there a more graceful way to get around this? (I'm using Zope 2.3.3/Python 1.5.2 at the moment). Sean ========================= Sean Upton Senior Programmer/Analyst SignOnSanDiego.com The San Diego Union-Tribune 619.718.5241 sean.upton@uniontrib.com =========================