Is it possible to toggle Play/Play Reverse?

I have tried with this code but it does not work, any ideas people?

// Set a toggle to play or playReverse the audio timeline

if (sym.getSymbol("button1Copy").isPlaying()) {

sym.getSymbol("button1Copy").playReverse();

} else {

sym.getSymbol("button1Copy").play();

}

thanks!

James