https://www.hkfin-jetso.com/blog/tap-go-%e8%a7%a3%e6%94%be%ef%bc%81iphone-%e9%83%bd%e7%94%a8%e5%be%97-%e6%96%b0%e7%99%bb%e8%a8%98%e5%8d%b3%e6%99%82%e9%80%81-50/