Trouble with classes

programming flash
1

I use two classes for my current project, a document class and a menuscreen class. I have a function in my document class called startGame that i want to run from the menuscreen class when a button is clicked. I’m nearly there but i’m getting an error when i try to run it:

1136: Incorrect number of arguments. Expected 1.

The error is at line 17 in the menuscreen class, the line that tries to run the function from the document class. I don’t understand what kind of argument it wants. Also, i’m not sure if the startGame function should be (event:Event) Hope someone can enlighten me on what’s wrong! Cheers! :beer:

DocumentClass

package 
{
    import flash.display.MovieClip;
    import flash.events.Event;

    public class DocumentClass extends MovieClip
    {

        public var menuScreen:MenuScreen;

        public function DocumentClass()
        {
            menuScreen = new MenuScreen();
            menuScreen.x = 0;
            menuScreen.y = 0;
            addChild( menuScreen );
        }
        
        public function startGame(event:Event)
        {
            // add play screen
            menuScreen = null;
        }
    }
}

MenuScreen class

package 
{
    import flash.display.MovieClip;
    import flash.events.MouseEvent;

    public class MenuScreen extends MovieClip
    {
        public var documentClass:DocumentClass;

        public function MenuScreen()
        {
            documentClass = new DocumentClass  ;
            startButton.addEventListener( MouseEvent.CLICK, onClick );
        }
        public function onClick(event:MouseEvent):void
        {
            documentClass.startGame()
        }
    }
}