docs: def generate_results_subparser(subparsers):
      """Adds a sub-command parser to `subparsers` to manipulate CSV
      results data."""
      parser = subparsers.add_parser(
          'results', description=constants.RESULTS_DESCRIPTION,
          epilog=constants.RESULTS_EPILOG, formatter_class=ParagraphFormatter,
          help=constants.RESULTS_HELP)
      utils.add_common_arguments(parser)
      parser.set_defaults(func=results)
      be_group = parser.add_argument_group('bifurcated extend')
      be_group.add_argument('-b', '--bifurcated-extend',
                            dest='bifurcated_extend', metavar='CORPUS',
                            help=constants.RESULTS_BIFURCATED_EXTEND_HELP)
      be_group.add_argument('--max-be-count', dest='bifurcated_extend_size',
                            help=constants.RESULTS_BIFURCATED_EXTEND_MAX_HELP,
                            metavar='COUNT', type=int)
      parser.add_argument('-e', '--extend', dest='extend',
                          help=constants.RESULTS_EXTEND_HELP, metavar='CORPUS')
      parser.add_argument('--excise', help=constants.RESULTS_EXCISE_HELP,
                          metavar='NGRAM', type=str)
      parser.add_argument('-l', '--label', dest='label',
                          help=constants.RESULTS_LABEL_HELP, metavar='LABEL')
      parser.add_argument('--min-count', dest='min_count',
                          help=constants.RESULTS_MINIMUM_COUNT_HELP,
                          metavar='COUNT', type=int)
      parser.add_argument('--max-count', dest='max_count',
                          help=constants.RESULTS_MAXIMUM_COUNT_HELP,
                          metavar='COUNT', type=int)
      parser.add_argument('--min-count-work', dest='min_count_work',
                          help=constants.RESULTS_MINIMUM_COUNT_WORK_HELP,
                          metavar='COUNT', type=int)
      parser.add_argument('--max-count-work', dest='max_count_work',
                          help=constants.RESULTS_MAXIMUM_COUNT_WORK_HELP,
                          metavar='COUNT', type=int)
      parser.add_argument('--min-size', dest='min_size',
                          help=constants.RESULTS_MINIMUM_SIZE_HELP,
                          metavar='SIZE', type=int)
      parser.add_argument('--max-size', dest='max_size',
                          help=constants.RESULTS_MAXIMUM_SIZE_HELP,
                          metavar='SIZE', type=int)
      parser.add_argument('--min-works', dest='min_works',
                          help=constants.RESULTS_MINIMUM_WORK_HELP,
                          metavar='COUNT', type=int)
      parser.add_argument('--max-works', dest='max_works',
                          help=constants.RESULTS_MAXIMUM_WORK_HELP,
                          metavar='COUNT', type=int)
      parser.add_argument('--ngrams', dest='ngrams',
                          help=constants.RESULTS_NGRAMS_HELP, metavar='NGRAMS')
      parser.add_argument('--reciprocal', action='store_true',
                          help=constants.RESULTS_RECIPROCAL_HELP)
      parser.add_argument('--reduce', action='store_true',
                          help=constants.RESULTS_REDUCE_HELP)
      parser.add_argument('--relabel', help=constants.RESULTS_RELABEL_HELP,
                          metavar='CATALOGUE')
      parser.add_argument('--remove', help=constants.RESULTS_REMOVE_HELP,
                          metavar='LABEL', type=str)
      parser.add_argument('--sort', action='store_true',
                          help=constants.RESULTS_SORT_HELP)
      utils.add_tokenizer_argument(parser)
      parser.add_argument('-z', '--zero-fill', dest='zero_fill',
                          help=constants.RESULTS_ZERO_FILL_HELP,
                          metavar='CORPUS')
      parser.add_argument('results', help=constants.RESULTS_RESULTS_HELP,
                          metavar='RESULTS')
      unsafe_group = parser.add_argument_group(
          constants.RESULTS_UNSAFE_GROUP_TITLE,
          constants.RESULTS_UNSAFE_GROUP_DESCRIPTION)
      unsafe_group.add_argument('--add-label-count', action='store_true',
                                help=constants.RESULTS_ADD_LABEL_COUNT_HELP)
      unsafe_group.add_argument('--add-label-work-count', action='store_true',
                                help=constants.RESULTS_ADD_LABEL_WORK_COUNT_HELP)
      unsafe_group.add_argument('--collapse-witnesses', action='store_true',
                                help=constants.RESULTS_COLLAPSE_WITNESSES_HELP)
      unsafe_group.add_argument('--group-by-ngram', dest='group_by_ngram',
                                help=constants.RESULTS_GROUP_BY_NGRAM_HELP,
                                metavar='CATALOGUE')
      unsafe_group.add_argument('--group-by-witness', action='store_true',
                                help=constants.RESULTS_GROUP_BY_WITNESS_HELP)