fix print_once undefined local
diff --git a/planetstack/observer/__init__.py b/planetstack/observer/__init__.py
index 9318ddb..d9a63be 100644
--- a/planetstack/observer/__init__.py
+++ b/planetstack/observer/__init__.py
@@ -25,6 +25,7 @@
 
 else:
     def notify_observer(model=None, delete=False, pk=None, model_dict={}):
+        global print_once
         if (print_once):
             print "The observer is disabled"
             print_once = False