PyUML is an open source Eclipse plug-in offering round trip engineering betwee UML and Python.UML support is limited to class diagrams and the code-generation capabilities are simple class to class (or interface to interface) transformations
Epydoc : Generate UML documentation from python code (last release on 2008)
PyNSource : Reverse engineer python source code into UML. Generated UML class diagrams can be displayed as ASCII Art or in a more typical graphical form.
Lumpy : Python module that generates UML diagrams (currently object and class diagrams) from a running Python program. It is similar to a graphical debugger in the sense that it generates a visualization of the state of a running program, but it is different from a debugger in the sense that it tries to generate high-level visualizations that are compliant (at least in spirit) with standard UML
ObjectDomain : commercial tool with forward and reverse engineering support for Python.
argoUML-python seems (seemed?) to go in the same direction but it is not quite there yet.