[Zope] how to call dtml method from python product and pass it namespace

Hello. From inside a python product I need to call a dtml method. When I call it, that dtml method can't find anything else in the folder. So - how can I pass it _ or whatever is needs so that it can find everything else in the folder? I tried passing it _, and passing it _=self, and various other things to no avail. Thanks, ^Roman