OnPlayStateChanged can not be use?

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Playables;

// A behaviour that is attached to a playable
public class NewPlayableBehaviour : PlayableBehaviour
{
// Called when the owning graph starts playing
public override void OnGraphStart(Playable playable) {

}

// Called when the owning graph stops playing
public override void OnGraphStop(Playable playable) {

}

// Called when the state of the playable is set to Play
public override void OnBehaviourPlay(Playable playable, FrameData info) {

}

public override void OnPlayStateChanged(FrameData info, PlayState newState)
{


}
// Called when the state of the playable is set to Paused
public override void OnBehaviourPause(Playable playable, FrameData info) {

}

// Called each frame while the state is set to Play
public override void PrepareFrame(Playable playable, FrameData info) {

}
}

 

Assets/NewPlayableBehaviour.cs(24,26): error CS0115: `NewPlayableBehaviour.OnPlayStateChanged(UnityEngine.Playables.FrameData, UnityEngine.Playables.PlayState)' is marked as an override but no suitable method found to override

 

https://docs.unity3d.com/560/Docume...rector.ScriptPlayable.OnPlayStateChanged.html

 

please let me know if any of it is amiss! thanks

 

private void OnPlayStateChanged(PlayState newState)
{
}