code: public Observable<List<HierarchicalEntityExtractor>> listHierarchicalEntitiesAsync(UUID appId, String versionId, ListHierarchicalEntitiesOptionalParameter listHierarchicalEntitiesOptionalParameter) {
          return listHierarchicalEntitiesWithServiceResponseAsync(appId, versionId, listHierarchicalEntitiesOptionalParameter).map(new Func1<ServiceResponse<List<HierarchicalEntityExtractor>>, List<HierarchicalEntityExtractor>>() {
              @Override
              public List<HierarchicalEntityExtractor> call(ServiceResponse<List<HierarchicalEntityExtractor>> response) {
                  return response.body();
              }
          });
      }
docs: Gets information about the hierarchical entity models.
  
  @param appId The application ID.
  @param versionId The version ID.
  @param listHierarchicalEntitiesOptionalParameter the object representing the optional parameters to be set before calling this API
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the List&lt;HierarchicalEntityExtractor&gt; object