XML Flash ActionScript

package{
  import flash.display.Sprite;
  
  public class Main extends Sprite{
    public function Main(){
        var example:XML = 
                              
                              
                              
                          
;
        example.appendChild();
        trace(example);
        
        example.prependChild();
        trace(example);
        
        example.insertChildAfter(example.b, );
        trace(example);
        
        example.insertChildBefore(example.f, );
        
        trace(example);
    }
  }
}