diff --git a/Tools/scripts/dutree.py b/Tools/scripts/dutree.py
index a49d80a..d938ae1 100755
--- a/Tools/scripts/dutree.py
+++ b/Tools/scripts/dutree.py
@@ -56,4 +56,5 @@
         if d.has_key(key):
             show(tsub, d[key][1], psub)
 
-main()
+if __name__ == '__main__':
+    main()