title: How do I sort CloudKit results by modified date?
body: <p>I'm trying to order search results by the modified date.
  If I wanted to do by creationDate its:</p>
  
  <pre><code>query.sortDescriptors = [NSSortDescriptor(key: "creationDate", ascending: false)]
  </code></pre>
  
  <p>What's the key for modified date?
  A list of all NSSortDescriptor keys or a way to find them would be extremely helpful.</p>