def get_node_by_key(self, key):
ch = self._hash_class(self.num_nodes)<EOL>machine = ch.get_machine(key)<EOL>node_id = self.node_ids[machine]<EOL>return self._connections[node_id]<EOL>
Get a machine based off the key that the clinet
            sends up.
            :return: `pinky.node.clinet.NodeClient` instance