title: __contains__ syntax
body: <p>Ive written a python program that used multiple instances of the <strong>contains</strong>  syntax to look inside dictionaries and lists.</p>
  
  <pre><code>if not test_map[var].__contains__(string):
  </code></pre>
  
  <p>It seems that I would of been better to use :</p>
  
  <pre><code>if string not in test_map[var]:
  </code></pre>
  
  <p>Does anyone know the issues that can occur is using the <code>__contains__</code> method ?</p>
  
  <p>Thanks,</p>