특히 아래쪽에 있는 것처럼 tk.Frame 자체를 수퍼클래스로 써서 하면 나중에 재활용하기도 편함
https://stackoverflow.com/questions/7300072/inheriting-from-frame-or-not-in-a-tkinter-application
https://stackoverflow.com/questions/7300072/inheriting-from-frame-or-not-in-a-tkinter-application
ㄱㅅ