Missing import
diff --git a/planetstack/core/models/site.py b/planetstack/core/models/site.py
index d3aef81..6fe40a6 100644
--- a/planetstack/core/models/site.py
+++ b/planetstack/core/models/site.py
@@ -1,5 +1,6 @@
 import os
 from django.db import models
+from django.db.models import Q
 from core.models import PlCoreBase,PlCoreBaseManager,PlCoreBaseDeletionManager
 from core.models import Tag
 from django.contrib.contenttypes import generic