title: While using tkinter, why should I use "indirect" callbacks?
body: <p>I am trying improve my Python and tkinter skills. At this moment I am reading a book on tkinter. I noticed that in an object oriented GUI application the author defines the button callbacks this way:</p>
  
  <pre><code>def on_fast_forward_button_clicked(self):
      self.player.fast_forward()
  
  def on_rewind_button_clicked(self):
      self.player.rewind()
  </code></pre>
  
  <p>So, if I understand correctly, we are writing to methods for each button in the application class. One with the "indirect" callback, called but the event, and other with the intended action itself, called by the previous one. Why should we write code like this, instead of just using a single method?</p>