title: Selectively triggering a model _post_put_hook
body: <p>I have set up a _post_put_hook on an ndb model that updates some search indexes. Which simplify data imports and atomic updates.
  But I have one case where I want to update certain properties of that model without triggering the indexing actions. </p>
  
  <p>So i'm looking for either:</p>
  
  <ol>
  <li>Some kind of flag that can be used with _post_put_hook, or:</li>
  <li>A way to know which model properties/values have changed on that put() so I can add a condition wether to update indexes or not.</li>
  </ol>
  
  <p>Thanks!</p>