public string ExitVehicle(string licensePlate, DateTime endTime, decimal payedMoney) { var vehicle = this.vehicleParkData.GetVehicle(licensePlate); if (vehicle == null) { return string.Format(Message.NoSuchVehicle, licensePlate); } var startTime = this.vehicleParkData.GetExpectedTimeForVehicle(vehicle); int endHours = (int)Math.Round((endTime - startTime).TotalHours); var parkedAt = this.vehicleParkData.GetParkedSpot(vehicle); var ticket = new Ticket(vehicle, payedMoney, parkedAt, endHours); this.vehicleParkData.RemoveVehicle(vehicle); return ticket.ToString(); }