def METHOD_NAME(cls, tmo=1):
    time.sleep(tmo)
    (status, output) = cls.target.run('umount %s' % cls.mount_point)
    if status == 32:
        # already unmounted, should it fail?
        return
    else:
        msg = ('Device not unmount %s' % cls.mount_point)
        cls.assertEqual(status, 0,  msg = msg)
    (status, output) = cls.target.run('cat /proc/mounts')
    match = re.search('%s' % cls.device, output)
    if match:
        msg = ('Device %s still mounted.' % cls.device)
        cls.assertTrue(match, msg = msg)