Here's my problem -- I'm using the ParsedXML product. I want to display, using the tree widget, a portion of the XML DOM tree. Now, the tree widget is controlled by a pair of methods, "branches" and "leaves". "leaves" is a DTML-Method called to render a leaf. "branches" specifies a method that generates a list of child note objects. In fact the default, tpValues is simply a call to the wrapped DOM to return the list childNodes. So, to control the output, I need to prune the list of childNodes to exclude the nodes I don't want to be included. The code for tpValues looks like def tpValues(self): retList={} for child in self.childNodes: retList.append(child) return retList Now, to decide whether to include a note or not, I need to look at the contents of the childNode, in particular, it's attributes. But how does one reference the child node instance to enquire about its nodeName, for example. The obvious approach child.__get_nodeName() fails in an External Method (the code is in the Python-level Extensions directory, not the Product's own Extension directory--is that a problem?). There are several layers of wrappers which complicates the problem. :-( There is the alternative "branches-expr" mechanism, but it appears to have the same reference questions. Thanks in advance for help.