code: def add_nodes(self, nodes):
          
          # Generalize nodes to a list
          if not isinstance(nodes, list):
              add_list = [nodes]
          else:
              add_list = nodes
          self.node_list.extend(add_list)
docs: Add a given node or list of nodes to self.node_list.
  
          Args:
              node (Node or list[Node]): the node or list of nodes to add
                  to the graph
  
          Returns: None
  
          Examples:
  
          Adding one node: ::
  
              >>> from blur.markov.node import Node
              >>> graph = Graph()
              >>> node_1 = Node('One')
              >>> graph.add_nodes(node_1)
              >>> print([node.value for node in graph.node_list])
              ['One']
  
          Adding multiple nodes at a time in a list: ::
  
              >>> from blur.markov.node import Node
              >>> graph = Graph()
              >>> node_1 = Node('One')
              >>> node_2 = Node('Two')
              >>> graph.add_nodes([node_1, node_2])
              >>> print([node.value for node in graph.node_list])
              ['One', 'Two']