@@ -59,11 +59,11 @@
             return self[key]
         else:
             return None
 
     def __setattr__(self, key, value):
-        if value == None:
+        if value is None:
             if key in self:
                 del self[key]
         else:
             self[key] = value
 
@@ -219,6 +219,8 @@
         return value
 
 if __name__ == '__main__':
     import doctest
     doctest.testmod()
+
+