Object to center with tween

1

I have problem to center my movie clip by tween class,
please check my file. I need the object to center and it goes to left…

import fl.transitions.Tween;
import fl.transitions.easing.*;
import fl.transitions.TweenEvent; 
stage.scaleMode = StageScaleMode.NO_SCALE;
stage.align = StageAlign.TOP_LEFT;

lang.x = stage.stageWidth / 2;
lang.y = stage.stageHeight / 2;

function sizeListener(e:Event):void {
	var my_x_Tween:Tween = new Tween(lang, "x", Regular.easeOut, stage.stageWidth / 2, 200, 2, true);
	var my_y_Tween:Tween = new Tween(lang, "y", Regular.easeOut, stage.stageHeight / 2, 200, 2, true);
}
stage.addEventListener(Event.RESIZE, sizeListener);