Parse a time stamp in the "year-month-day hour-minute" format.

def parse_time_arg(s):
    """
    Parse a time stamp in the "year-month-day hour-minute" format.
    """
    try:
        return time.strptime(s, "%Y-%m-%d %H:%M")
    except ValueError as e:
        raise argparse.ArgumentTypeError(e)