Hello master, i'm back and still so amateur in developing AR

I want my 3D object will play sound everytime my image target is detected, so i follow the script created by AlessandroB

public class ImageTargetPlayAudio : MonoBehaviour,
                                            ITrackableEventHandler
{
    private TrackableBehaviour mTrackableBehaviour;
 
    void Start()
    {
        mTrackableBehaviour = GetComponent<TrackableBehaviour>();
        if (mTrackableBehaviour)
        {
            mTrackableBehaviour.RegisterTrackableEventHandler(this);
        }
    }
     
    public void OnTrackableStateChanged(
                                    TrackableBehaviour.Status previousStatus,
                                    TrackableBehaviour.Status newStatus)
    {
        if (newStatus == TrackableBehaviour.Status.DETECTED ||
            newStatus == TrackableBehaviour.Status.TRACKED ||
            newStatus == TrackableBehaviour.Status.EXTENDED_TRACKED)
        {
            // Play audio when target is found
            audio.Play();
        }
        else
        {
            // Stop audio when target is lost
            audio.Stop();
        }
    }   
}

Then i get the best error which i dont get it on this part 

mTrackableBehaviour.RegisterTrackableEventHandler(this);

The error says

The Best Overloaded Method match for 'Vuforia.TrackableBehaviour.RegisterTrackableEventHandler(Vuforia.ITrackableEventHandler)' has some invalid argument

Argument '1' : cannot conver from 'ImageTargetPlayAudio' to 'Vuforia.ITrackableEventHandler'

Please help me, thank you in advance