[Zope] Session Management for keeping Python-Objects

Hello, I have an external method that returns a python-object to zope. Inside zope i would like to be able to store the object as a session variable in order to have access to this object inside one session. I have tried to do this using FSSession, but it's not able to pickle objects to a file. Which session management product would you propose for doing this? Thanks for any input, stephan