title: Remove elements from a list that are contained in other list
body: <p>I have two lists</p>
  
  <p>users</p>
  
  <pre><code>[[[u'1-tpbvixq4-j1mjkfcl'], [u'1-oufnhv4b-j1tbyxvt']], 2, None]
  </code></pre>
  
  <p>constrained_users</p>
  
  <pre><code>[[[u'1-oufnhv4b-j1tbyxvt']], 1, None]
  </code></pre>
  
  <p>I'm trying to remove <code>constrained_users</code> from <code>users</code>, but I'm not being able to do it.</p>
  
  <p>This is my code, trying to match them so far:</p>
  
  <pre><code>if any(users[0][0] in u for u in constrained_users[0]):
      print "true"
  else:
      print "false"
  </code></pre>
  
  <p>But I'm always getting false.</p>
  
  <p>How can I remove the <code>constrained_users</code> from <code>users</code>?</p>