public void RemoveSetOfRegistrationNumber(List <string> RegistrationNumbers)
 {
     foreach (var number in RegistrationNumbers)
     {
         if (AllCars.Any(x => x.RegistrationNumber == number.ToString()))
         {
             this.AllCars.RemoveAll(x => x.RegistrationNumber == number);
         }
     }
 }
 public string RemoveCar(string registrationNumber)
 {
     if (!AllCars.Any(x => x.RegistrationNumber == registrationNumber))
     {
         return("Car with that registration number, doesn't exist!");
     }
     else
     {
         AllCars.Remove(AllCars.Where(x => x.RegistrationNumber == registrationNumber).FirstOrDefault());
         return($"Successfully removed {registrationNumber}");
     }
 }
 public string AddCar(Car car)
 {
     if (AllCars.Any(x => x.RegistrationNumber == car.RegistrationNumber))
     {
         return("Car with that registration number, already exists!");
     }
     if (Count >= Capacity)
     {
         return("Parking is full!");
     }
     else
     {
         AllCars.Add(car);
         return($"Successfully added new car {car.Make } {car.RegistrationNumber}");
     }
 }