public FavoritesService(IKenticoFavoritesProvider kenticofavorites)
        {
            if (kenticofavorites == null)
            {
                throw new ArgumentNullException(nameof(kenticofavorites));
            }

            this.kenticofavorites = kenticofavorites;
        }
        public ProductsService(IKenticoProductsProvider products, IKenticoFavoritesProvider favorites, IKenticoResourceService resources)
        {
            if (products == null)
            {
                throw new ArgumentNullException(nameof(products));
            }
            if (favorites == null)
            {
                throw new ArgumentNullException(nameof(favorites));
            }
            if (resources == null)
            {
                throw new ArgumentNullException(nameof(resources));
            }

            this.products  = products;
            this.favorites = favorites;
            this.resources = resources;
        }