https://blog.faceutil.com/2017/03/15/%ec%83%89%ec%83%81-%ec%b6%94%ec%b6%9c-%ed%94%84%eb%a1%9c%ea%b7%b8%eb%9e%a8-color-cop%ec%9c%bc%eb%a1%9c-%ec%83%89-%ec%b6%94%ec%b6%9c%ed%95%98%ea%b8%b0-%e3%83%ae/