#2503 make singletons compared with "is" not == or !=
Thanks to Wummel for the patch
diff --git a/Mac/scripts/buildpkg.py b/Mac/scripts/buildpkg.py
index 7f635a0..ed5c88f 100644
--- a/Mac/scripts/buildpkg.py
+++ b/Mac/scripts/buildpkg.py
@@ -183,7 +183,7 @@
 
         # set folder attributes
         self.sourceFolder = root
-        if resources == None:
+        if resources is None:
             self.resourceFolder = root
         else:
             self.resourceFolder = resources