public String toString(){
		String str = "Performance name:" + name + "\nIncluding:";
		for(Artist a : artists){
			str += "\n\t" + a.getName();
		}
		str += "\nAt " + startTime + " till " + endTime + "\nOn stage " + stage.getName() + " with expected popularity " + popularity + "\n -------";
		return str;
	}