title: Nullable date in Freemarker
body: <p>This is a piece of my freemarker template:</p>
  
  <pre>
  ${order.needByDate?if_exists?date}
  </pre>
  
  <p>I want it to work as following:</p>
  
  <ul>
  <li>if <code>needByDate</code> is null, then write nothing</li>
  <li>if it is not null, then write the date part</li>
  </ul>
  
  <p>The above works only in second scenario. What is the correct way to achieve this?</p>