code: def get_node_list(self):
          
          node_objs = list()
  
          for obj_dict_list in self.obj_dict['nodes'].values():
              node_objs.extend([
                  Node(obj_dict=obj_d)
                  for obj_d
                  in obj_dict_list])
  
          return node_objs
docs: Get the list of Node instances.
  
          This method returns the list of Node instances
          composing the graph.