def clone_graph_visited(self, node, visited_set):
        """
        post-order traversal
        Time Limit Exceeded
        :param node:
        :param visited_set:
        :return:
        """
        if not node:
            return
        visited_set.add(node)
        neighbors_cloned = [self.clone_graph_visited(neighbor, set(visited_set)) for neighbor in node.neighbors if neighbor not in visited_set]
        node_cloned = UndirectedGraphNode(node.label)
        for neighbor_cloned in neighbors_cloned:
            if visited_set not in neighbor_cloned:
                neighbor_cloned.neighbors.append(node_cloned)
        node_cloned.neighbors = neighbors_cloned
        return node_cloned
dataset/ETHPy150Open algorhythms/LeetCode/133 Clone Graph.py/Solution.clone_graph_visited/swapped operands of `not in`