[Zope-dev] "ZCatalog-aware ZClasses"

I saw this question asked, but didn't see an answer - what's a "ZCatalog-aware ZClass" involve? looking at the ZCatalog source, it looks like one way would be to make the code that adds the object instance search for a ZCatalog object, then call catalog.catalog_object(object, objecturl) - and the delete method should then call catalog.uncatalog_object(objecturl). Is it just a matter of making a single class that does just this, and make the ZClasses you build inherit from it? Or is there a simpler way? Anthony