code: public Jsonable microServiceSuccess(String microservice, ServiceSummary serviceSummary) {
          MicroserviceList microserviceList = serviceSummary.getMicroservices(microservice);
          if (microserviceList != null) {
              for (MicroserviceInstance instance : microserviceList.getInstances()) {
                  List<Invocation> invocations = instance.getInvocations();
                  if (invocations != null) {
                      for (Invocation invocation : invocations) {
                          if (invocation.getStatus().getCode() == Status.OK.getCode() ||
                                  invocation.getStatus().getCode() == Status.CREATED.getCode()) {
                              return invocation;
                          }
                      }
                  }
                  List<Update> updates = instance.getUpdates();
                  if (updates != null) {
                      for (Update update : updates) {
                          if (update.getStatus().getCode() == Status.OK.getCode() ||
                                  update.getStatus().getCode() == Status.CREATED.getCode()) {
                              return update;
                          }
                      }
                  }
              }
          }
          // Now check all children ServiceSummaries
          if (serviceSummary.getChildServiceSummaryList() != null) {
              for (ServiceSummary child : serviceSummary.getChildServiceSummaryList()) {
                  Jsonable match = microServiceSuccess(microservice, child);
                  if (match != null)
                      return match;
              }
          }
          return null;
      }
docs: <p>
  Looks through the service summary for a successful completion for a
  certain microservice:
  <li>1. First checks the invocations for a 200 or 201 response</li>
  <li>2. If none found then checks the updates for a 200 or 201 Completion
  response</li>
  </p>
  
  @param microservice
  to check for successful completion
  @param serviceSummary
  object to check for successful completions
  @see ServiceSummary
  @return a Jsonable as a future-proof in case we need to know which
  invocation/update was successful
  @throws JSONException