code: def main(argv: Sequence[str] = SYS_ARGV) -> int:
      
      args = default_parser().parse_args(argv)
  
      try:
          seq = POPULATIONS[args.population]  # type: Sequence
      except KeyError:
          try:
              with open(args.population, 'r', encoding=args.encoding) as file_:
                  seq = list(file_)
          except (OSError, UnicodeError) as ex:
              print(ex, file=sys.stderr)
              return 1
  
      main_key = key(seq=seq, nteeth=args.nteeth, delimiter=args.delimiter)
      print(main_key)
  
      if args.stats:
          print('*', len(main_key), 'characters')
          print('*', args.nteeth, 'samples from a population of', len(seq))
          print(
              '* entropy {sign} {nbits} bits'.format(
                  sign='~' if args.delimiter else '<',
                  nbits=round(math.log(len(seq), 2) * args.nteeth, 2),
              ),
          )
  
      return 0
docs: Execute CLI commands.