diff --git a/pisi/graph.py b/pisi/graph.py
index e0dd636f..eb8552c5 100644
--- a/pisi/graph.py
+++ b/pisi/graph.py
@@ -1,5 +1,8 @@
 # the most simple minded digraph class ever
 
+# for python 2.3 compatibility
+from sets import Set as set
+
 class CycleError:
     pass