How to use the serialio.UNLOCK_SUCCESSFUL function in serialio

s.adapter.set_tclk(0)
    # Run target serial clock at 1.5MHz
    s.adapter.set_sclk(127)

    try:
        code = args.code.decode('hex')
    except TypeError:
        logging.fatal("Code must be in hexadecimal format.")
        return
    if len(code) != 7:
        logging.fatal("Code must be 7 bytes long.")
        return

    s.unlock(code)
    status = s.unlock_status()
    if status != serialio.UNLOCK_SUCCESSFUL:
        logging.fatal("Target did not unlock.")
        return
    logging.info("Target unlocked.")

    start = 0x0e00
    end = 0x0fff

    with open(args.output, 'w') as f:
        logging.info("Writing pages {:x}-{:x} to {}...".format(start, end,
                                                               args.output))
        for page in range(start, end+1):
            logging.debug("Dumping {:x}00-{:x}ff...".format(page, page))
            data = s.read_page(page)
            f.write(data)