ActionScript 3.0 :: 2D SpaceShooter - Title Screen Play Button

I'm trying to make a 2D SpaceShooter for my Flash Class and so far i have the Game working. All I need to add is a menu screen where it says to hit play and a play agian button when you lose. I'm working on my menu screen right now and I get an annoying error saying

ScreenTitle.as,Line7
1084:Syntax error:expecting identifier before right brace {

Here is the code:
package {
import flash.events.MouseEvent;
import flash.events.Event;
public class ScreenTitle extends {
public static const PLAY:String = "";
public function ScreenTitle() {
play_mc.buttonMode = true;
play_mc.addEventListener(MouseEvent.CLICK, clickPlay);
} public function clickPlay(e:MouseEvent) {
dispatchEvent(new Event(PLAY));
}}}