new_contents: from tkinter import *
  class App(Frame):
      def __init__(self, master=None):
          Frame.__init__(self, master)
          self.pack()
  myapp = App()
  myapp.master.title("Meu programa")
  myapp.master.minsize(600, 400)
  myapp.mainloop()
  
subject: Create MinhaJanela.py