https://medium.com/@pjba02im19z/%E9%80%9A%E8%BF%87%E6%B4%BB%E5%8A%A8%E8%8E%B7%E5%8F%96quant%E7%A9%BA%E6%8A%95%E7%9A%84%E6%96%B9%E6%B3%95-30270d1e79a6