https://blog.wongcw.com/2022/05/10/bollinger%e5%ae%a3%e5%b8%83%e5%ba%95%e7%89%b9%e5%be%8b%e5%85%ac%e5%8f%b8roush%e7%82%ba%e5%85%b6%e9%9b%bb%e5%8b%95%e5%95%86%e7%94%a8%e8%bb%8a%e8%a3%bd%e9%80%a0%e5%a4%a5%e4%bc%b4/