--- a/app/soc/logic/models/base.py	Wed Oct 22 16:55:35 2008 +0000
+++ b/app/soc/logic/models/base.py	Wed Oct 22 17:03:08 2008 +0000
@@ -151,6 +151,9 @@
           of this entity.
     """
 
+    if not entity:
+      return None
+    
     suffix = []
 
     for field in entity.KEY_FIELDS: