docs: def positive_int(value: str) -> int:
      """
      ``argparse`` argument type that checks that its value is a positive
      integer.
      """
      try:
          ivalue = int(value)
          assert ivalue > 0
      except (AssertionError, TypeError, ValueError):
          raise ArgumentTypeError(
              "{!r} is an invalid positive int".format(value))
      return ivalue