missing info on -[MPMediaLibrary getPlaylistWithUUID:creationMetadata:completionHandler:]

I'm so pleased to see in the iOS 9.3 API Diffs document:

MPMediaLibrary.h


Added -[MPMediaLibrary getPlaylistWithUUID:creationMetadata:completionHandler:]


And I see in MPMediaLibrary.h:


/!

* Finds the playlist associated with the UUID.

* If the playlist exists, the creation metadata is ignored.

* If no such playlist exists and creation metadata is valid, a playlist associated the UUID will be created.

*

* @discussion The UUID should typically be pre-generated to avoid creating a new playlist with every call.

*/

- (void)getPlaylistWithUUID:(NSUUID *)uuid creationMetadata:(nullable MPMediaPlaylistCreationMetadata *)creationMetadata completionHandler:(void (^)(MPMediaPlaylist * __nullable playlist, NSError * __nullable error))completionHandler NS_AVAILABLE_IOS(9_3);


But beyond those hints, the new API is a mystery to me. I can imagine how to use it, but don't know how to configure an MPMediaPlaylistCreationMetadata nor am I sure of the use. Does anyone have any ideas as to how to use this or how best to find info on new APIs with unfinished documentation?