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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 add_nodes(self, nodes, attr_dict=None, **attr):
 """Adds multiple nodes to the graph, along with any related attributes of the nodes. :param nodes: iterable container to either references of the nodes OR tuples of (node reference, attribute dictionary); if an attribute dictionary is provided in the tuple, its values will override both attr_dict's and attr's values. :param attr_dict: dictionary of attributes shared by all the nodes. :param attr: keyword arguments of attributes of the node; attr's values will override attr_dict's values if both are provided. See also: add_node Examples: :: ("B", {label="negative"}), ("C", {root=True})] """

        attr_dict = self._combine_attribute_arguments(attr_dict, attr)

        for node in nodes:
            # Note: This won't behave properly if the node is actually a tuple
            if type(node) is tuple:
                # See ("B", {label="negative"}) in the documentation example
                new_node, node_attr_dict = node
                # Create a new dictionary and load it with node_attr_dict and
                # attr_dict, with the former (node_attr_dict) taking precedence
                new_dict = attr_dict.copy()
                new_dict.update(node_attr_dict)
                self.add_node(new_node, new_dict)
            else:
                # See "A" in the documentation example
                self.add_node(node, attr_dict.copy())