gotoAndStop with button in class

programming flash
1

Hello, I am trying to create a button class that will gotoAndStop at a specific frame, however I seem unable to…I was wondering if anyone has any suggestions on what to do here. My code is as follows:

package {
import flash.events.MouseEvent;
import flash.display.SimpleButton;
import flash.display.FrameLabel;

public class PlayButton extends SimpleButton {

    public function PlayButton() {
        this.addEventListener(MouseEvent.MOUSE_DOWN, expand);
    }
    private function expand(event:MouseEvent):void{
        gotoAndStop(2);
    }

}

}

The error I get is error 1180:Call to a possible undefined method gotoAndStop.

Thanks!