https://blog.gongquiz.com/2021/04/08/%eb%a9%94%ed%83%80%eb%8d%b0%ec%9d%b4%ed%84%b0metadata%ec%9d%98-%ea%b8%b0%eb%b3%b8%ec%a0%81%ec%9d%b8-%ec%9a%94%ec%86%8c%ea%b0%80-%ec%95%84%eb%8b%8c-%ea%b2%83%ec%9d%80-%ec%a7%80%ec%a0%81%ec%82%b0/