[Zope3-Users] recursive constraints

[Markus Leist]

Hello,

there are a few (older) mails about "recursive constraints" in Zope3.
I wasn't able to find a solution for this small problem:

in interface.py:
------------------------
class IIkGroup(IIkSClass):
    def __setitem__(name, object):
        """Add a IIkGroup object."""
    __setitem__.precondition = ItemTypePrecondition( IIkInterface)
[...]
------------------------

only Instances of IkInterface are allowed to add, ok so far.

Now it should be possible to add an Instance of IkGroup (on itself)?
"... ItemTypePrecondition( IIkGroup, IIkInterface) ..." is a stupid idea, because
pathon don't know IIkGroup() at this time.

I don't wont to implement an "IContained"-mechanism and 
setTaggedValue... seems to be obsolete - is this possible?

Markus