https://blog.wongcw.com/2020/10/29/pal-v%e4%b8%89%e8%bc%aa%e9%a3%9b%e8%a1%8c%e6%b1%bd%e8%bb%8aliberty%e5%9c%a8%e6%ad%90%e7%8d%b2%e8%aa%8d%e8%ad%89%e5%8f%af%e4%bb%a5%e4%b8%8a%e8%b7%af%e5%8f%88%e4%b8%8a%e5%a4%a9/