#!/usr/bin/python3"""Demonstrate parenthesis drops in argparse metavar."""import argparse# The very first and last parentheses disappear in the usage line, but are# present in the argument list.parser = argparse.ArgumentParser(    description='Demonstrate parenthesis drops in argument meta-descriptions')parser.add_argument(    'positional',    help='positional argument',    metavar='(example) positional')parser.add_argument(    '-p',    '--optional',    help='optional argument',    type=int,    choices=[1, 2],    metavar='{1 (option A), 2 (option B)}',    default=1)arguments = parser.parse_args()print(arguments)

usage: parens.py [-h] [-p {1 option A), 2 (option B)}] (example positionalDemonstrate parenthesis drops in argument meta-descriptionspositional arguments:  (example) positional  positional argumentoptional arguments:  -h, --help            show this help message and exit  -p {1 (option A), 2 (option B)}, --optional {1 (option A), 2 (option B)}                        optional argument