Hello Following example 18.3.1 and 18.3.2 from phillkon's book, i'm trying to define a MySite class in Zope 2.12, which look like this: class IMySite(IPossibleSite, IContainer): """ """ id = ASCIILine( ... name = TextLine( ... class MySite(SiteManagerContainer, BTreeContainer): implements(IMySite) So far so good, i've an interface and a class extending SiteManagerContainer and BTreeContainer. Problem becomes when i want to define the add form. If i'm not wrong, I cannot use the same machinery as zope3, so i was trying to use formlib: class MySiteAddForm(AddForm): form_fields=form.Fields(IListo) And i doesn't work. The error i'm getting is: NotImplementedError: concrete classes must implement create() or createAndAdd() I was looking info about them but i wonder i'm running with a conceptual gap here, because this is the same problem i had to define MySite inheriting from Folder. The same problem happened there, i was able to define the class but when i needed the form i wasn't able to use formlib and i used old-zope2-like-code. Probably i could try to do smt like that, but i'm very curious to see how can i use formlib in such cases. The question then is, is it possible or would it make sense to do something like this ?. Do you know about a sample code that could be helpful ?. Any comment or hint would be very appreciated. Kind Regards r. -- http://robertoallende.com