I don't know what you mean exactly by "reverse engineer" but here are some tools that can generate UML diagrams from python code (scroll down to UML Tools for Python):http://modeling-languages.com/uml-tools/#python
EDIT: Hmmm, some of those tools also use the term "reverse engineer". Looks more like just translating to me but I guess they can do what you're looking for. I'll have to check them out myself. UML diagrams are pretty enlightening sometimes.