[Zope] How do I make an external object a subclass of Persistence.Persistent?

Hi, I'm following up on a tip by Michel Pelletier that I make an external object persistent in the Zope process by subclassing it from Persistence.Persistent. But lib/python/Persistence.py is essentially an empty file. What am I missing? ------------------------------------------------------ Andres Corrada-Emmanuel Email: andres@corrada.com Owner http://www.corrada.com/mamey Mamey Phone: (413) 587-9595 ------------------------------------------------------