diff --git a/pisi/delta.py b/pisi/delta.py
index 1b19c770..a331ff11 100644
--- a/pisi/delta.py
+++ b/pisi/delta.py
@@ -111,7 +111,8 @@ def find_delta(oldfiles, newfiles):
         deltas.extend(hashto_files[h])
 
     # Directory hashes are None. There was a bug with PolicyKit that should have an empty directory.
-    deltas.extend(hashto_files[None])
+    if hashto_files.has_key(None):
+        deltas.extend(hashto_files[None])
 
     return deltas