This is something that I still don't quite understand. I have a set of (python, Folder derived) objects, which are children of a Folder derived python class. Each of these in turn has another, related python object. / a ab1 ab2 ab3 b1 b2 b3 When I access /a/ab1, I want b1 inserted into the acquisition hierarchy between a and ab1. I've done this with __bobo_traverse__, but that doesn't help when you access ab1 as an attribute of a, such as when using objectValues(). So I thought I would try overriding __of__, like so in the ab class: def __of__(self, parent): wparent = self._b.__of__(parent) return Folder.Folder.__of__(self, wparent) But that doesn't work, I get this error on the return line: Error Type: TypeError Error Value: unbound C method must be called with Acquirer 1st argument Any ideas? I'm pretty confused. Thanks, -Randy