title: Generic List firstOrDefault
body: <p>I have a generic list and trying to get item based on value i.e.,</p>
  
  <pre><code>list.FirstOrDefault(u=&gt;u.Key == key) // error 'T' does not contain definition for 'Key'
  </code></pre>
  
  <p>The generic type <code>T</code> having different base classes.</p>