diff --git a/oml/user/models.py b/oml/user/models.py
index 22d76e9..f5c812d 100644
--- a/oml/user/models.py
+++ b/oml/user/models.py
@@ -307,7 +307,7 @@ class List(db.Model):
 
     @classmethod
     def rename_user(cls, old, new):
-        for l in cls.query.filter(cls._query is not None):
+        for l in cls.query.filter(cls._query != None):
 
             def update_conditions(conditions):
                 changed = False
@@ -320,7 +320,7 @@ class List(db.Model):
                             changed = True
                 return changed
 
-            if update_conditions(l._query.get('conditions', [])):
+            if l._query and update_conditions(l._query.get('conditions', [])):
                 l.save()
 
     def add_items(self, items, commit=True):