+        self.odd=gridlib.GridCellAttr()
+        self.odd.SetBackgroundColour("sky blue")
+        self.even=gridlib.GridCellAttr()
+        self.even.SetBackgroundColour("sea green")
+
+    def GetAttr(self, row, col, kind):
+        attr = [self.even, self.odd][row % 2]
+        attr.IncRef()
+        return attr
+