[Zope-CMF] Re: Content types based on Python objects

[Philipp von Weitershausen]

Charlie Clark wrote:
> 
> Am 28.11.2007 um 14:03 schrieb Charlie Clark:
> 
>> class Grid(dict, PortalContent)
>> ...
>>
>> TypeError: Error when calling the metaclass bases multiple bases have 
>> instance lay-out conflict
> 
> 
> Looks like using the old favourite UserDict solve the incompatability 
> problem.
> 
> class Grid(UserDict, PortalContent):
> ...
> 

Right. You can't mix built-in types with ExtensionClasses (pretty much 
anything in Zope 2 is an ExtensionClass). Actually, subclassing the 
built-in types usually only works for trivial cases.

UserDict (or PersistentDict) is the right thing to use here.