Enterprise Architect (http://www.sparxsystems.com.au/) supports an add-in that will generate Python from UML diagrams. Once you install EA, follow the instructions for adding the Python technology resource, which is a free download from the EA website.
Will also generate UML from Python source. You'll need to buy the Professional Edition to get code import/export, US$189, but it is an excellent tool! -- Paul -- http://mail.python.org/mailman/listinfo/python-list
