generating objects of a type from a name.

[chris.lyon at spritenote.co.uk]

I'm trying to generate visual python objects from django objects and
therefore have objects called  'Ring' and 'Cylinder' as django objects
and I want to create objects of those names in visual.
I can cludge it in varius ways by using dir and lots of if lookups but
is there a  way of doing this that allows the name to generate a
visual object of the appropriate name or fail nicely if the visual
object doesn't exist?