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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 get_node(self, name):
 r""" Get a tree node structure. The structure is a dictionary with the following keys: * **parent** (*NodeName*) Parent node name, :code:`''` if the node is the root node * **children** (*list of NodeName*) Children node names, an empty list if node is a leaf * **data** (*list*) Node data, an empty list if node contains no data :param name: Node name :type name: string :rtype: dictionary :raises: * RuntimeError (Argument \`name\` is not valid) * RuntimeError (Node *[name]* not in tree) """

        if self._validate_node_name(name):
            raise RuntimeError("Argument `name` is not valid")
        self._node_in_tree(name)
        return self._db[name]