#2503 make singletons compared with "is" not == or !=
Thanks to Wummel for the patch
diff --git a/Lib/plat-mac/PixMapWrapper.py b/Lib/plat-mac/PixMapWrapper.py
index 7edbac2..62297b3 100644
--- a/Lib/plat-mac/PixMapWrapper.py
+++ b/Lib/plat-mac/PixMapWrapper.py
@@ -146,9 +146,9 @@
         """Draw this pixmap into the given (default current) grafport."""
         src = self.bounds
         dest = [x1,y1,x2,y2]
-        if x2 == None:
+        if x2 is None:
             dest[2] = x1 + src[2]-src[0]
-        if y2 == None:
+        if y2 is None:
             dest[3] = y1 + src[3]-src[1]
         if not port: port = Qd.GetPort()
         Qd.CopyBits(self.PixMap(), port.GetPortBitMapForCopyBits(), src, tuple(dest),