title: How to display variables in a MessageBox
body: <p>I have this code:</p>
  
  <pre><code> def OnClick(self, event):
       lan1 = self.a.Getvalue()
       lan2 = self.b.Getvalue()
  </code></pre>
  
  <p>Now I want to use a MessageBox, which should display the <code>lan1</code> and <code>lan2</code> values in it.</p>
  
  <p>How can I do this?</p>