code: public List<HierarchicalEntityExtractor> listHierarchicalEntities(UUID appId, String versionId, ListHierarchicalEntitiesOptionalParameter listHierarchicalEntitiesOptionalParameter) {
          return listHierarchicalEntitiesWithServiceResponseAsync(appId, versionId, listHierarchicalEntitiesOptionalParameter).toBlocking().single().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
  @throws ErrorResponseException thrown if the request is rejected by server
  @throws RuntimeException all other wrapped checked exceptions if the request fails to be sent
  @return the List&lt;HierarchicalEntityExtractor&gt; object if successful.