https://www.syu.ac.kr/blog/apple-developer-academy-3%ea%b8%b0-%ea%b5%90%ec%9c%a1%ec%83%9d-%eb%aa%a8%ec%a7%91-%eb%b0%8f-%ec%84%a4%eb%aa%85%ed%9a%8c-%ec%95%88%eb%82%b4/%ec%95%a0%ed%94%8c-%eb%94%94%eb%b2%a8%eb%a1%9c%ed%8d%bc-%ec%95%84%ec%b9%b4%eb%8d%b0%eb%af%b8-3%ea%b8%b0-%eb%aa%a8%ec%a7%91%ec%9a%94%ea%b0%95-%ec%98%a8%eb%9d%bc%ec%9d%b8-%ec%84%a4%eb%aa%85%ed%9a%8c_1/