public static Object mul(Object o1, Object o2){
		
		if (o1 instanceof List && o2 instanceof Number){
			List newList = new ArrayList();
			for (int i=0;i<((Number)o2).intValue();i++){
				newList.addAll((List)o1);
			}
			return newList;
		}
		
		if (o1 instanceof String){
			if (o2 instanceof Number){
				StringBuilder builder = new StringBuilder();
				for (int i=0;i<((Number)o2).intValue();i++){
					builder.append(o1);
				}
				return builder.toString();
			}
			return o1;
		} 
		if (o1 instanceof Integer && o2 instanceof Integer){
			return ((Integer)o1) * ((Integer)o2);
		} else {
			return ((Number)o1).doubleValue() * ((Number)o2).doubleValue();
		}
	}