[Zope] How can I "from __future__ import nested_scopes" in python scripts?

Hi All, I'm using Zope2.4 beta with Python 2.1 and I want to use the nest_scope functionality. However when I add the prerequisite statement: from __future__ import nested_scopes at the top of my python script it gives me an "ImportError" and "unauthorized" message. By default the nested scopes are not included. How do I this work? Jelle --