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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def postorder(self, skip_seed=False):
 """ Return a generator that yields the nodes of the tree in postorder. If skip_seed=True then the root node is not included. """

        for node in self._tree.postorder_node_iter():
            if skip_seed and node is self._tree.seed_node:
                continue
            yield node