Add 'if __name__ == "__main__":' to files already as a usable as a module.
diff --git a/Demo/scripts/fact.py b/Demo/scripts/fact.py
index 5497f66..03cab8b 100755
--- a/Demo/scripts/fact.py
+++ b/Demo/scripts/fact.py
@@ -45,4 +45,5 @@
         except EOFError:
             pass
 
-main()
+if __name__ == "__main__":
+    main()