[Zope] objectValues &c for base class?

[Anthony Baxter]

If I've got a bunch of ZClasses, all derived from the same base ZClass,
is there an easy way to say 'give me a list of all objects whose class 
or base class is foo'?

Sort of like what the current objectValues &c does, but being able to
specify the meta_types of the base classes, rather than having to enumerate
all the possible different classes.

What about if all the classes are in the same Product in 
Control_Panel/Products? Could you filter based on product?

ta,
Anthony