title: tkinter quit crash
body: <p>I am very new to Tkinter. I made this "Hello World"-like GUI program in Tkinter. However, every time I click on the quit button, the program crashes. Thanks in advance!</p>
  
  <pre><code>from Tkinter import *
  import sys
  class Application(Frame):
  
  def __init__(self,master=None):
  
      Frame.__init__(self,master=None)
      self.grid()
      self.createWidgets()
  
  def createWidgets(self):
      self.quitButton = Button(text='Quit',command=self.quit)#Problem here
      self.quitButton.grid()
  app = Application()
  app.master.title("Sample application")
  app.mainloop()
  </code></pre>