[tkinter] trouble running imported modules in main program

[snakeinmyboot]

>if __name__ == '__main__':
>     root = tkinter.Tk()
>     app = MainClass(root)  # 'MainClass' depends on the module.
>     root.mainloop
>     root.destroy 

for REAL you guys...wtf does this even mean lol. what is a boilerplate test code?