[Zope] xmDateTime Substitute for Zope?

[complaw@hal-pc.org]

An application has need for the RelativeDateTime() feature of mxDateTime. 
However, if one tries (in a python script)...

from mx.DateTime import *

.. Zope returns an error message indicating that the attempted import was
unauthorized.

Does anyone know of a substitute?  Or how the problem could be circumvented?

What I'm really looking for is a way to calculate the date 20 months from
now().  mxDateTime has a handy feature for that, which would simply be:

LaterDate = now() + RelativeDateTime(months=+20)

Would this be possible via an External Method or is there a way for Zope to do
the arithmatic without needing mxDateTime?

Thanks in advance,

Ron