Can I play a custom sound in watchos 3 on the watch speakers

I've read that we can now play custom sounds on the apple watch in watchos 3. I've read a few places that I'll have to use SceneKit. Can someone place a simple example of this. I'm not using SceneKit in my app as I don't need it but if that's the only way to play a custom sound then I'd like to know the minimum code required to accomplish this. Preferrably in Objective c but I'll take it in whatever shape.

Here's what I have so far but it doesn't work:

SCNNode * audioNode = [[SCNNode alloc] init];

SCNAudioSource * audioSource = [SCNAudioSource audioSourceNamed:@"mysound.mp3"];

SCNAudioPlayer * audioPlayer = [SCNAudioPlayer audioPlayerWithSource:audioSource];

[audioNode addAudioPlayer:audioPlayer];

SCNAction * play = [SCNAction playAudioSource:audioSource waitForCompletion:YES];

[audioNode runAction:play];