public boolean addShow(Show show){
        if (show instanceof Movie){
            if (showExists(show)){
                return false;
            }else {
                Movie tmp = new Movie((Movie) show);
                shows.add(tmp);
            }
        }else{
            if (showExists(show)){
                return false;
            }else {
                Theatrical tmp = new Theatrical((Theatrical) show);
                shows.add(tmp);
            }
        }
        return true;
    }