public TopicRepository(AmazonAccountSettings amazonAccountSettings, IAmazonSnsFacade amazonSnsFacade)
        {
            amazonAccountSettings.Requires("amazonAccountSettings").IsNotNull();
            amazonSnsFacade.Requires("amazonSnsFacade").IsNotNull();

            this.amazonAccountSettings = amazonAccountSettings;
            this.amazonSnsFacade = amazonSnsFacade;
        }
        public AmazonSnsFacade(AmazonAccountSettings amazonAccountSettings)
        {
            amazonAccountSettings.Requires("amazonAccountSettings").IsNotNull();

            amazonSnsFactory = () =>
                AWSClientFactory.CreateAmazonSimpleNotificationServiceClient(amazonAccountSettings.AccessKey,
                    amazonAccountSettings.SecretKey,
                    amazonAccountSettings.RegionEndPoint.
                        ToRegionEndpoint());
        }