public string UpdateVehicleState(string i_LicenseNumber, string i_StringNewVehicleState)
        {
            Vehicle vehicle = SearchVehicle(i_LicenseNumber);

            if (vehicle != null)
            {
                vehicle.VehicleStatus = Vehicle.GetVehicleState(i_StringNewVehicleState);
                return("Vehicle state was updated successfully");
            }
            else
            {
                return("Vehicle was not found");
            }
        }
        public string DisplayVehiclesLicenses(string i_VehicleState)
        {
            if (m_GarageVehicles.Count == 0)
            {
                return("There are no existing vehicles");
            }
            else
            {
                StringBuilder         vehicleLicenses = new StringBuilder();
                Vehicle.eVehicleState vehicleState    = Vehicle.GetVehicleState(i_VehicleState);

                foreach (Vehicle vehicle in m_GarageVehicles)
                {
                    if (vehicle.VehicleStatus == vehicleState)
                    {
                        vehicleLicenses.Append(vehicle.LicenseNumber + "\n");
                    }
                }

                return(vehicleLicenses.ToString());
            }
        }