def add_children(self,*sub_nodes):
     NodeSet.add_children(self, *sub_nodes)
     for n in sub_nodes:
         c=n._downcast(klass=Contact)
         MembershipLog(village=self, contact=c, action='C').save()
def _group(name, *children):
    g=NodeSet(debug_id=name)
    g.save()
    g.add_children(*children)
    return g