http://docs.php.net/manual/kr/language.oop5.decon.php

https://ddorai-dumok.blogspot.com/2018/01/php-chm.html

https://www.php.net/manual/en/index.php

https://codeigniter-kr.org/user_guide_2.1.0/general/controllers.html#constructors

https://www.cikorea.net/bbs/view/qna?idx=17304&page=26&hit=not

https://xe1.xpressengine.com/tip/19377585

https://www.cikorea.net/bbs/view/tip?idx=8298&page=10&hit=not

https://riptutorial.com/ko/php/example/6503/아이를-인스턴스화-할-때-부모-생성자를-호출

Missing parent constructor call 

 Inspection info: Reports the constructors that do not call their parent constructor.

Old-Style constructor 

 Inspection info: Reports old-style constructor declarations (ClassName()) and suggests replacing them with new-style constructors (__construct()).