def process_args(default_concur_req):
    server_options = ', '.join(sorted(SERVERS))
    parser = argparse.ArgumentParser(
                description='Download flags for country codes. '
                'Default: top 20 countries by population.')
    parser.add_argument('cc', metavar='CC', nargs='*',
                help='country code or 1st letter (eg. B for BA...BZ)')
    parser.add_argument('-a', '--all', action='store_true',
                help='get all available flags (AD to ZW)')
    parser.add_argument('-e', '--every', action='store_true',
                help='get flags for every possible code (AA...ZZ)')
    parser.add_argument('-l', '--limit', metavar='N', type=int,
                help='limit to N first codes', default=sys.maxsize)
    parser.add_argument('-m', '--max_req', metavar='CONCURRENT', type=int,
                default=default_concur_req,
                help='maximum concurrent requests (default={})'
                      .format(default_concur_req))
    parser.add_argument('-s', '--server', metavar='LABEL',
                default=DEFAULT_SERVER,
                help='Server to hit; one of {} (default={})'
                      .format(server_options, DEFAULT_SERVER))
    parser.add_argument('-v', '--verbose', action='store_true',
                help='output detailed progress info')
    args = parser.parse_args()
    if 1 < args.max_req:
        print('*** Usage error: --max_req CONCURRENT must be >= 1')
        parser.print_usage()
        sys.exit(1)
    if args.limit < 1:
        print('*** Usage error: --limit N must be >= 1')
        parser.print_usage()
        sys.exit(1)
    args.server = args.server.upper()
    if args.server not in SERVERS:
        print('*** Usage error: --server LABEL must be one of',
              server_options)
        parser.print_usage()
        sys.exit(1)
    try:
        cc_list = expand_cc_args(args.every, args.all, args.cc, args.limit)
    except ValueError as exc:
        print(exc.args[0])
        parser.print_usage()
        sys.exit(1)

    if not cc_list:
        cc_list = sorted(POP20_CC)
    return args, cc_list
dataset/ETHPy150Open fluentpython/example-code/17-futures/countries/flags2_common.py/process_args/swapped operands of `<`