[AS3] Check to see if MovieClip Exsists

I’m being a little dense today, I swear I’ve done this so many times before, but it’s just not working out.

Is there a way to see if a MovieClip exists within another MovieClip that has a class applied to it?

My code:


package{
    
    import flash.display.MovieClip;
    
    public class Test extends MovieClip{
        
        public function Test(){
            trace('Test!');
            trace(box2);
            if(box3){
                trace('box 3 extsists');
            }else{
                trace('no box 3');
            }
        }
        
        public function create():void{
            this.graphics.beginFill(0x000000);
            this.graphics.drawRect(0, 0 , 10, 10);
            this.graphics.endFill();
        }
        
    }
}