Using addChild inside a package / class

Hello Everyone, I am trying to do my first big project in AS3 and am having some trouble.

I have a symbol, Frame. I want a class to manage my frames, so I made one, called FrameManager. I want FrameManager to be able to add frames to the stage, but it doesn’t seem to be able to access it.

package {
import flash.display.MovieClip;

public class FrameManager {
    function FrameManager(){
        var myFrame:Frame = new Frame();
        addChild(myFrame); // Doesn't work, undefined
    }
}

}

Am I able to do this? I could have FrameManager extend something, add it to the stage, then add children to it, but I’d rather just add it to the stage.