/// <summary>
        ///
        /// </summary>
        /// <param name="customer"></param>
        /// <returns></returns>
        public async Task <PromoRule> AddAsync(PromoRule customer)
        {
            var requestUrl = string.Format(BaseUrl, StoreId);

            using (var client = CreateMailClient(requestUrl))
            {
                var response = await client.PostAsJsonAsync(string.Empty, customer).ConfigureAwait(false);

                await response.EnsureSuccessMailChimpAsync().ConfigureAwait(false);

                var promoRuleResponse = await response.Content.ReadAsAsync <PromoRule>().ConfigureAwait(false);

                return(promoRuleResponse);
            }
        }
        /// <summary>
        /// The update async.
        /// </summary>
        /// <param name="cartId"></param>
        /// <param name="cart"></param>
        /// <returns>
        /// The <see cref="Task"/>.
        /// </returns>
        public async Task <PromoRule> UpdateAsync(string promoRuleID, PromoRule promoRule)
        {
            var requestUrl = string.Format(BaseUrl, StoreId);

            using (var client = CreateMailClient(requestUrl + "/"))
            {
                var response = await client.PatchAsJsonAsync(promoRuleID, promoRule).ConfigureAwait(false);

                await response.EnsureSuccessMailChimpAsync().ConfigureAwait(false);

                var promoRuleResponse = await response.Content.ReadAsAsync <PromoRule>().ConfigureAwait(false);

                return(promoRuleResponse);
            }
        }