code: def check_nonnegative(value):
      value_as_int = int(value)
      if value_as_int < 0:
          raise argparse.ArgumentTypeError(
              "%s is an invalid value. Only non-negative integers allowed."
              % value
          )
      return value_as_int
  
label_desc: Use image node_id 1 for calling a global function with example usage: check_nonnegative(value) and returns: value_as_int