docs: def parse_args():
      """Parses the arguments and options."""
      parser = argparse.ArgumentParser(
          prog="geneparse-indexer",
          description="Genotype file indexer."
      )
  
      # IMPUTE2 files
      group = parser.add_argument_group("IMPUTE2 index")
      group.add_argument(
          "--impute2", metavar="IMPUTE2", type=str, nargs="+",
          help="Index an IMPUTE2 genotype file format. The file can be plain "
               "text or bgzipped.",
      )
  
      # BGEN files
      group = parser.add_argument_group("BGEN index")
      group.add_argument(
          "--bgen", metavar="BGEN", type=str, nargs="+",
          help="Index a BGEN genotype file. This requires 'bgenix' to be in the "
               "PATH.",
      )
      group.add_argument(
          "--legacy", action="store_true",
          help="Index the file using the '-with-rowid' option. This flag "
               "enables compatibility with SQLITE prior to version 3.8.2. See "
               "https://bitbucket.org/gavinband/bgen/wiki/bgenix for more "
               "information.",
      )
  
      return parser.parse_args()