[Zope] Using "Class-Hierarchies" in Zope

Hi, I've got a question regarding ZClasses and the building of Hierarchies using them. For example I have ZClass A and the ZClasses B and C "derived" from A What does Zope do if I create a new Instance of B using manage_addProduct['myproduct'].B_add(myparam). I know that the B_add Script I created is called, but is also the A_add Script called, or can I call it in the B_add script, or do I have to reimplement all necessary things from A_add in B_add? Andreas -- There is a fly on your nose.