Argparse vs docopt

argparser_comp.py

"""SMTP user checker.

Usage:
  argparser_comp.py SERVER USERNAMES [(-p <p>| --port=<p>)]
  argparser_comp.py (-h | --help)

Options:
  -h --help          Show this screen.
  -p <p> --port=<p>  SMTP port of server [default: 25].

"""
import os.path
import argparse
from docopt import docopt


def is_file(f):
    if os.path.isfile(f):
        return f
    raise OSError("{} does not exist".format(f))


def parse_args():
    parser = argparse.ArgumentParser(description="SMTP user checker")
    parser.add_argument('server', help="IP address of server")
    parser.add_argument('usernames', type=is_file,
                        help="Path to list of user names")
    parser.add_argument('--port', '-p', type=int,
                        default=25, help="SMTP port of server")
    return parser.parse_args()


def parse_args2():
    args = docopt(__doc__)
    return argparse.Namespace(server=args["SERVER"],
                              usernames=is_file(args["USERNAMES"]),
                              port=int(args["--port"]))

  
if __name__ == "__main__":
    args1 = parse_args()
    args2 = parse_args2()
    assert args1 == args2