Command line tool to convert from iCalendar to Remind

def ics2rem():
    """Command line tool to convert from iCalendar to Remind"""
    from argparse import ArgumentParser, FileType
    from sys import stdin, stdout

    parser = ArgumentParser(description='Converter from iCalendar to Remind syntax.')
    parser.add_argument('-l', '--label', help='Label for every Remind entry')
    parser.add_argument('-p', '--priority', type=int,
                        help='Priority for every Remind entry (0..9999)')
    parser.add_argument('-t', '--tag', action='append',
                        help='Tag(s) for every Remind entry')
    parser.add_argument('--tail',
                        help='Text to append to every remind summary, following final %%"')
    parser.add_argument('--sep', default=" ",
                        help='String to separate summary (and tail) from description')
    parser.add_argument('--postdate',
                        help='String to follow the date in every Remind entry. '
                        'Useful for entering "back" and "delta" fields (see man remind).')
    parser.add_argument('--posttime',
                        help='String to follow the time in every timed Remind entry. '
                        'Useful for entering "tdelta" and "trepeat" fields (see man remind).')
    parser.add_argument('-z', '--zone',
                        help='Timezone of Remind file (default: local timezone)')
    parser.add_argument('infile', nargs='?', type=FileType('r'), default=stdin,
                        help='Input iCalendar file (default: stdin)')
    parser.add_argument('outfile', nargs='?', type=FileType('w'), default=stdout,
                        help='Output Remind file (default: stdout)')
    args = parser.parse_args()

    zone = timezone(args.zone) if args.zone else None

    vobject = readOne(args.infile.read())
    rem = Remind(localtz=zone).to_reminders(
        vobject, args.label, args.priority, args.tag, args.tail, args.sep,
        args.postdate, args.posttime)
    args.outfile.write(rem)