code: def convert_to_broker_id(string):
      
      error_msg = 'Positive integer or -1 required, {string} given.'.format(string=string)
      try:
          value = int(string)
      except ValueError:
          raise argparse.ArgumentTypeError(error_msg)
      if value <= 0 and value != -1:
          raise argparse.ArgumentTypeError(error_msg)
      return value
docs: Convert string to kafka broker_id.