public async Task <Result <IEnumerable <ProductViewModel> > > Handle(GetAllProductsQuery query, CancellationToken cancellationToken)
            {
                var productList = await _productRepository.ViewModelListAllAsync();

                if (productList == null)
                {
                    return(Result <IEnumerable <ProductViewModel> > .Failure($"Product List Empty."));
                }
                return(Result <IEnumerable <ProductViewModel> > .Success(productList));
            }