Swift 3. NSFetchRequest propertiesToFetch
<p>In Swift 3 when we use <code>NSFetchRequest</code>, we have to specify <code>NSFetchRequestResult</code>. But how to get an array of properties values? If I use something like this</p>

<pre><code>let fetchRequest = NSFetchRequest&lt;MyClass&gt;(entityName: "MyClass")
fetchRequest.propertiesToFetch = ["myAttributeName"]
</code></pre>

<p>an exception fires when I try to execute fetch request.
<code>error: -executeRequest: encountered exception = The database appears corrupt.</code>
If I remove a line with <code>propertiesToFetch</code> I don't get any errors, but I get an array of objects, not properties.</p>