Passing variable to event listener

Hi another dumb question I guess but how do you pass a variable to a listener function? Im trying to add bmp when the mouse goes over this class but i keep getting the undefined error.

package FlashPackage{
    import flash.display.*;
    import flash.ui.Mouse;

    public class SomeClass extends Sprite{
        public function SomeClass(){
        var img:BitmapData = new BitmapData(20,20,false,0xFF0000FF);
        var bmp:Bitmap = new Bitmap(img);
        bmp.x = 100;
        bmp.y = 100;
        addEventListener(Event.ADDED_TO_STAGE, handler);

        function handler(e:Event):void{
            addEventListener(MouseEvent.MOUSE_OVER, MouseOVER);

        function MouseOVER(e:MouseEvent):void{