https://medium.com/@perryleozhw/celo-dollar-%E7%A9%BA%E6%8A%95-%E8%8E%B7%E5%8F%96%E5%85%8D%E8%B4%B9%E4%BB%A3%E5%B8%81%E7%9A%84%E8%AF%A6%E7%BB%86%E6%93%8D%E4%BD%9C%E6%AD%A5%E9%AA%A4-2ab96a54ab4c