[Zope] Accessing ZClasses other ZClasses via Python

[Klaus Woelfel]

Hi,
Can anybody tell me how I can access a ZClass in another ZClass with python?

For example I have a ZClass, called "foo_class" that lifes in another ZClass 
called "Container_class" in a product called "foo_product".

So this works fine: 
"Control_Panel.Products.foo_product.Container_class"

But this doesn't work: 
"Control_Panel.Products.foo_product.Container_class.foo_class"

Zope says: 

Error Type: AttributeError
Error Value: foo_class

Can anybody help me?
ciao,
	Klaus