I've been looking into ways to generate python code from UML. I tried Enterprise Architect from Sparx systems, which is indeed an impressive product, but since the code generation lacked features I wished for anyway, I thought looking into the open source alternatives might be worth it.
I tried some UML tools like Umbrello, Gaphor, StarUML etc but they all were either not mature enough, or had problems running on Linux or Linux/Wine.
I finally settled on ArgoUML, which feels mature enough. And there is the ArgoUML-python plugin, for python code generation (see also this question on StackOverflow, for a background to my choice). Unfortunately there is no binaries available for download, so you have to build them yourself. That was not much of a hassle at all in Eclipse though, so I'll go through the steps here: