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?