Can't display drawing circle

1

I try to display a simple circle in the stage but it doesn’t work.

Here’s the code:

package {

import flash.display.Sprite;
import flash.display.Shape;

public class circles extends Sprite {

    public function circles() {
    
    var green:Shape = _createCircle(0x00FF00, 10);
    green.x = 25;
    green.y = 25;

    addChild(green);
    }


   private function _createCircle(color: uint, radius: int):Shape {
        var circle:Shape = new Shape();
        circle.graphics.beginFill(color);
        circle.graphics.drawCircle(0, 0, radius);
        circle.graphics.endFill();
        return circle;
    }
}

}

What’s wrong with the code?