public void CreatePlantGroup(string gardenName, string plantGroupName, string accountID) { if (string.IsNullOrEmpty(gardenName)) { throw new ArgumentException("message", nameof(gardenName)); } if (plantGroupName == null) { throw new ArgumentNullException(nameof(plantGroupName)); } Garden garden = GardenRepository.GetByName(gardenName, accountID); PlantGroup plantGroup = new PlantGroup(plantGroupName); PlantGroupRepository.CreatePlantGroup(garden, plantGroup, accountID); garden.AddPlantGroup(plantGroup); GardenRepository.AddPlantGroup(garden, plantGroup, accountID); //should be update }