def test_1(self):
        a = TreeNode(1)
        b = TreeNode(2)
        c = TreeNode(3)
        a.left = b
        a.right = c

        self.assertEqual(lot.levelOrder(a), [[1],[2,3]])
    def test_something(self):
        a = TreeNode(2)
        b = TreeNode(1)
        a.left = b

        c = bi.Solution(a)
        self.res = []
        while c.hasNext():
            self.res.append(c.next())

        self.assertEqual(self.res, [1,2])
    def test_1(self):
        a = TreeNode(1)
        b = TreeNode(2)
        c = TreeNode(3)
        d = TreeNode(4)
        e = TreeNode(5)
        a.left = b
        a.right = c
        c.left = d
        c.right = e

        self.assertEqual(lot.levelOrder(a), [[1],[2,3],[4,5]])