How to use SKAudioNode

I found out SKAction playSoundFileNamed does memory leak in IOS 9: https://forums.developer.apple.com/thread/20014

They recommend to use SKAudioNode, but the example is swift and i use objective-c in my project.

Example:

func testAudioNode() {  
    let audioNode = SKAudioNode(fileNamed: "LevelUp")  
    audioNode.autoplayLooped = false  
    self.addChild(audioNode)  
    let playAction = SKAction.play()  
    audioNode.runAction(playAction)  
}  

What i have tried:

-(void)testSound{
testSound = [SKAudioNode nodeWithFileNamed:@"test.wav"];
testSound.autoplayLooped = false;
[self addChild:testSound];

SKAction *playaction = [SKAction play];

[testSound runAction:playaction];
}

It will crash to:

[self addChild:testSound];

So how i would get it work, what is good technique for play sounds with SKAudioNode only in IOS 9> and with SKAction in older versions?

Thanks!