--- a/graphics/RubberBand.py	Tue Aug 15 16:48:49 2017 +0300
+++ b/graphics/RubberBand.py	Tue Aug 15 17:01:51 2017 +0300
@@ -61,7 +61,7 @@
         Indicate if rubberband is drawn on viewer
         @return: True if rubberband is drawn
         """
-        return self.CurrentBBox != None
+        return self.CurrentBBox is not None
 
     def GetCurrentExtent(self):
         """