added is_predicate property at class leverl

maybe this should be _is_predicate ?


git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@2356 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5/Document/PredicateGroup.py

@@ -46,6 +46,7 @@ class PredicateGroup(Folder, Predicate):
   add_permission = Permissions.AddPortalContent
   isPortalContent = 1
   isRADContent = 1
+  is_predicate = 1
 
   _operators = (
     {