public static void Start()
{
vehicleCollection = new Collections(TYPES_PATH, VEHICLE_PATH, RENT_PATH);
vehicleCollection.Print();
vehicleCollection.Insert(-1, AddNewVehicle()); // add new vehicle
vehicleCollection.Delete(1);
vehicleCollection.Delete(4);
Console.WriteLine("\nCollection after modify:");
vehicleCollection.Print();
vehicleCollection.Sort();
Console.WriteLine("\nCollection after sort by model name:");
vehicleCollection.Print();
}