code: def nx_gen_node_values(G, key, nodes, default=util_const.NoParam):
      
      node_dict = nx_node_dict(G)
      if default is util_const.NoParam:
          return (node_dict[n][key] for n in nodes)
      else:
          return (node_dict[n].get(key, default) for n in nodes)
docs: Generates attributes values of specific nodes