title: How to add a title to each subplot
body: <p>I have one figure which contains many subplots.</p>
  
  <pre><code>fig = plt.figure(num=None, figsize=(26, 12), dpi=80, facecolor='w', edgecolor='k')
  fig.canvas.set_window_title('Window Title')
  
  # Returns the Axes instance
  ax = fig.add_subplot(311) 
  ax2 = fig.add_subplot(312) 
  ax3 = fig.add_subplot(313) 
  </code></pre>
  
  <p>How do I add titles to the subplots?</p>
  
  <p><code>fig.suptitle</code> adds a title to all graphs and although <code>ax.set_title()</code> exists, the latter does not add any title to my subplots. </p>
  
  <p>Thank you for your help.</p>
  
  <p>Edit:
  Corrected typo about <code>set_title()</code>. Thanks Rutger Kassies </p>