code: public Observable<UUID> addHierarchicalEntityAsync(UUID appId, String versionId, HierarchicalEntityModel hierarchicalModelCreateObject) {
          return addHierarchicalEntityWithServiceResponseAsync(appId, versionId, hierarchicalModelCreateObject).map(new Func1<ServiceResponse<UUID>, UUID>() {
              @Override
              public UUID call(ServiceResponse<UUID> response) {
                  return response.body();
              }
          });
      }
docs: Adds a hierarchical entity extractor to the application version.
  
  @param appId The application ID.
  @param versionId The version ID.
  @param hierarchicalModelCreateObject A model containing the name and children of the new entity extractor.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the UUID object