[Zope] Edit ZClass Properties

Hi, The problem I'm trying to solve is how to change the values of properties of a ZClass from a python script. Simple assignment does not work, e.g. myZClass['aProperty'] = value I did a web search and found some HOWTOs mentioning a method 'manage_editProperties'. I could not find any documentation about this method in 'The Zope Book' or the Zope help. Is there another place to look for API documentation that I am not aware of? My main question is: what is the procedure to change properties of a ZClass programatically? Thanks. --Borislav