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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 nodes(self):
 """A |Nodes| collection of all required nodes. Note that the required outlet node is added: Nodes("node_1123", "node_1125", "node_11269", "node_1129", "node_113", "node_outlet") It is both possible to change the prefix names of the nodes and the name of the outlet node separately: Nodes("b_1123", "b_1125", "b_11269", "b_1129", "b_113", "l_node") """

        return (
            devicetools.Nodes(
                self.node_prefix+routers for routers in self._router_numbers) +
            devicetools.Node(self.last_node))