title: Find object in a python list using the 'in' operator
body: <p>Is it possible to do something that looks like this:</p>
  
  <pre><code>if obj in a_list_of_the_same_obj_type:
       #do stuff
  </code></pre>
  
  <p>My obj already have the <code>__eq__</code> and <code>__ne__</code> function that compare on an attribute so I thought the <code>in</code> keyword would call it but it doesn't look like it does. </p>