def __swapValues(self, node1, a1, node2, a2):
        """ Swap any two values in nodes """
        if node1 is not node2:
            idx1, idx2 = node1.values.index(a1), node2.values.index(a2)
            node1.values[idx1], node2.values[idx2] = node2.values[idx2], node1.values[idx1]
 Swap any two values in nodes 
recipes/Python/577898_23_Tree/recipe-577898.py