public static string ImportCars(CarDealerContext context, string inputJson)
        {
            IEnumerable<CarInputModel> dtoCars = JsonConvert.DeserializeObject<IEnumerable<CarInputModel>>(inputJson);

            List<Car> cars = new List<Car>();

            foreach (CarInputModel dtoCar in dtoCars)
            {
                Car newCar = new Car
                {
                    Make = dtoCar.Make,
                    Model = dtoCar.Model,
                    TravelledDistance = dtoCar.TravelledDistance,
                };
                foreach (int partId in dtoCar.PartsId.Distinct())
                {
                    newCar.PartCars.Add(new PartCar
                    {
                        PartId = partId
                    });
                }

                cars.Add(newCar);
            }

            context.Cars.AddRange(cars);
            context.SaveChanges();

            return $"Successfully imported {cars.Count()}.";
        }