My simple iterative Python solution
\nclass Solution(object):\n    def postorder(self, root):\n        """\n        :type root: Node\n        :rtype: List[int]\n        """\n        \n        if r
```\nclass Solution(object):\n    def postorder(self, root):\n        """\n        :type root: Node\n        :rtype: List[int]\n        """\n        \n        if root is None:\n            return []\n        \n        stack_1, stack_2 = [root], []\n\n        while stack_1:\n            node = stack_1.pop();\n            stack_2.append(node.val)\n            [stack_1.append(ch) for ch in node.children]\n                          \n        return [stack_2.pop() for i in range(len(stack_2))]\n```
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