old_contents: from Tkinter import Label
  
  def showLabel():
      widget = Label(None, text='Hello!')
      widget.pack()
  
new_contents: from Tkinter import Label
  
  class displaywWindow:
      " This class display the window of paperpass "
      def showLabel():
          widget = Label(None, text='Hello!')
          widget.pack()
  
subject: put showLabel function into displayWindow class as a method