:-( Right, I have a Python product with a __call__ method that is (hopefully) going to be used to render a navigation tree. To do this (and have the tree expand in the right places) I need a list of objects that need to be expanded. I'm currently using the following expression to get this list: objects = copy(self.REQUEST.PARENTS) objects.reverse() Now, to this I need to append the PARENTS[0-1] object, if you see what I mean. In DTML, it would be this(), but I'm stumped as to what I should append in Python. self is just the navigator object. If I redefine __call__ as def __call__(self, client, REQUEST) I just get a TypeError: Error value: not enough arguments; expected 3, got 1 If I use a safer signature def __call__(self,client=None) then client is always None, and so not what I'm after at all. I had a look at DTMLMethod.py and PythonMethod.py to try and get a clue btu just got very scared. Can someone please help me out here? cheers, Chris PS: If there's a totally different way to get the containment list of objects that need to be expanded, I'd love to hear it :-)