Add 'if __name__ == "__main__":' to files already as a usable as a module.
diff --git a/Demo/scripts/mboxconvert.py b/Demo/scripts/mboxconvert.py
index ba1f734..502d774 100755
--- a/Demo/scripts/mboxconvert.py
+++ b/Demo/scripts/mboxconvert.py
@@ -120,4 +120,5 @@
     print
     return sts
 
-main()
+if __name__ == "__main__":
+    main()