[Zope] How to create a global variable?

Hi! I've a python script which creates a dictionnary each time it's called. This dictionnary is always the same. I would increase the performance if I could generate and cache the dictionnary once, then reuse it. I'm looking for a space like REQUEST.SESSION that is the same for each user of my website (other solutions are welcome). Do you know how to do that? Thank you.