public override void Invoke(AWSCredentials creds, RegionEndpoint region, int maxItems)
        {
            AmazonStepFunctionsConfig config = new AmazonStepFunctionsConfig();

            config.RegionEndpoint = region;
            ConfigureClient(config);
            AmazonStepFunctionsClient client = new AmazonStepFunctionsClient(creds, config);

            ListActivitiesResponse resp = new ListActivitiesResponse();

            do
            {
                ListActivitiesRequest req = new ListActivitiesRequest
                {
                    NextToken = resp.NextToken
                    ,
                    MaxResults = maxItems
                };

                resp = client.ListActivities(req);
                CheckError(resp.HttpStatusCode, "200");

                foreach (var obj in resp.Activities)
                {
                    AddObject(obj);
                }
            }while (!string.IsNullOrEmpty(resp.NextToken));
        }