def METHOD_NAME(self):
    #          -------PEER IDS------
    #   NUM    0    1    2    3    4
    good_chains_info = [
        (8, ['d', 'd', 'i', 'i', 'p']),
        (7, ['c', 'c', 'c', 'c', 'o']),
    ]
    bad_chains_info = [
        (6, ['b', 'b', '', 'b', 'n']),
        (5, ['a', 'a', '', 'a', '']),
        (4, ['0', '0', '', '0', '']),
    ]
    good_chains = make_chains(good_chains_info)
    bad_chains = make_chains(bad_chains_info)
    tails, _ = get_tails(good_chains)
    graph, errors = build_fork_graph(bad_chains, tails)
    self.assertEqual(errors, [2, 4])
    node_id_map = get_node_id_map(errors, len(good_chains))
    tails = list(map(
        lambda item: item[1],
        filter(
            lambda item: item[0] not in errors,
            sorted(tails.items()))))
    print_summary(graph, tails, node_id_map)