There is a questions asking how to simulate static variables in python.
Also, on the web one can find many different solutions to create static variables. (Though I
From one of your comments: "I'd like to use them to cache things loaded from disk. I think it clutters the instance less, if I could assign them to the function"
Use a caching class then, as a class or instance attribute to your other class. That way, you can use the full feature set of classes without cluttering other things. Also, you get a reusable tool.
This shows that on SO it always pays off to state one's problem instead of asking for a specific, low level solution (e.g. for a missing language feature). That way, instead of endless debates about simulating "static" (a deprecated feature from an ancient language, in my view) someone could have given a good answer to you problem sooner.