code: def build_arg_parser2():
      
      usage_str = "Smatch calculator -- arguments"
      parser = optparse.OptionParser(usage=usage_str)
      parser.add_option("-f", "--files", nargs=2, dest="f", type="string",
                        help='Two files containing AMR pairs. AMRs in each file are ' \
                             'separated by a single blank line. This option is required.')
      parser.add_option("-r", "--restart", dest="r", type="int", help='Restart number (Default: 4)')
      parser.add_option('--significant', dest="significant", type="int", default=2,
                        help='significant digits to output (default: 2)')
      parser.add_option("-v", "--verbose", action='store_true', dest="v", help='Verbose output (Default:False)')
      parser.add_option("--vv", "--veryverbose", action='store_true', dest="vv",
                        help='Very Verbose output (Default:False)')
      parser.add_option("--ms", "--multiple_score", action='store_true', dest="ms",
                        help='Output multiple scores (one AMR pair a score) instead of ' \
                             'a single document-level smatch score (Default: False)')
      parser.add_option('--pr', "--precision_recall", action='store_true', dest="pr",
                        help="Output precision and recall as well as the f-score. Default: false")
      parser.add_option('--justinstance', action='store_true', default=False,
                        help="just pay attention to matching instances")
      parser.add_option('--justattribute', action='store_true', default=False,
                        help="just pay attention to matching attributes")
      parser.add_option('--justrelation', action='store_true', default=False,
                        help="just pay attention to matching relations")
      parser.set_defaults(r=4, v=False, ms=False, pr=False)
      return parser
docs: Build an argument parser using optparse. Use it when python version is 2.5 or 2.6.