title: Fetch only Live Photos using Photos Framework dosen't work
body: <p>I'm trying to fetch only Live Photos out of the device albums.
  I found this Objective C code, but for some reason when converting it to Swift to doesn't compile.</p>
  
  <pre><code>PHFetchOptions *options = [[PHFetchOptions alloc] init];
  options.predicate = [NSPredicate predicateWithFormat: @"(mediaSubtype == %ld)", PHAssetMediaSubtypePhotoLive];
  options.sortDescriptors = @[[NSSortDescriptor sortDescriptorWithKey: @"creationDate" ascending: NO]];
  PHFetchResult&lt;PHAsset *&gt; *assetsFetchResults = [PHAsset fetchAssetsWithMediaType: PHAssetMediaTypeImage options: options];
  </code></pre>
  
  <p>Swift:</p>
  
  <pre><code> fetchOptions.predicate = NSPredicate(format: "mediaSubtype == %ld", PHAssetMediaSubtype.PhotoLive)
  </code></pre>
  
  <p>throws compile error :</p>
  
  <pre><code> Argument type 'PHAssetMediaSubtype' does not conform to expected type 'CVarArgType'
  
  Any suggestions?
  </code></pre>