--- a/entity.py	Fri Apr 02 16:10:35 2010 +0200
+++ b/entity.py	Fri Apr 02 17:27:53 2010 +0200
@@ -901,7 +901,7 @@
         """add relations to the given object. To set a relation where this entity
         is the object of the relation, use 'reverse_'<relation> as argument name.
 
-        Values may be an entity, a list of entity, or None (meaning that all
+        Values may be an entity, a list of entities, or None (meaning that all
         relations of the given type from or to this object should be deleted).
         """
         # XXX update cache