title: replacing a new interface with old one in tkinter
body: <p>I've created a class that has a function called mainScreen(). It simply prints the main screen with two buttons on it. If you press any button, it must go to another function called signup(). I want to clear the whole frame and create new widgets but I can't clear the widgets</p>
  
  <pre><code>class graphics:
      def __init__(self, master):
      self.root = master
  
  
      def mainscreen(self):
          helv36 = tkFont.Font(family='Century Gothic', size=20)
          mainFrame = Frame(self.root)
          mainFrame.config(relief='sunken', width=1280, height=720, bg='light 
  blue')
          mainFrame.pack(expand='yes', fill='both')
          inButton = Button(mainFrame, text = "Sign up", bd = 10, relief = 
  GROOVE, font = helv36)
          inButton.bind("&lt;Button-1&gt;", self.signup)
          inButton.place(bordermode = OUTSIDE, width =160, height = 60, x = 
  600, y = 300)
          upButton = Button(mainFrame, text = "Sign in", bd = 10, relief = 
  GROOVE, font = helv36)
          upButton.bind("&lt;Button-1&gt;", self.signup)
          upButton.place(bordermode = OUTSIDE, width =160, height = 60, x = 
  600, y = 400)
          mainFrame.pack_propagate(FALSE)
          self.root.mainloop()
  
      def signup(self,event):
          signUpShow = Frame(self.root)
          signUpShow.config(relief='sunken', width=1280, height=720, bg='light 
  yellow')
          signUpShow.pack(expand='yes', fill='both')
  </code></pre>