I have two classes. The first one (the starting class):

package
{
    import flash.display.Sprite;
    import flash.events.KeyboardEvent;
    import tetris.*;

    public class TetrisGame extends Sprite
    {

        private var _gameWell:Well;

        public function TetrisGame()
        {    
            _gameWell = new Well();
            addChild(_gameWell);
        } 
    }
}

The second:

package tetris
{
    import flash.display.Sprite;
    import flash.events.KeyboardEvent;

    public class Well extends Sprite
    {

        public function Well()
        {
            super();

            addEventListener(KeyboardEvent.KEY_DOWN, onKeyboard);
        }

        private function onKeyboard(event:KeyboardEvent):void
        {
            //some code is here
        }


    }
}

But when I press any buttons on my keyboard, the child class Well doesn't have any reaction. What's the problem?