code: public ClosedListEntityExtractor getClosedList(UUID appId, String versionId, UUID clEntityId) {
          return getClosedListWithServiceResponseAsync(appId, versionId, clEntityId).toBlocking().single().body();
      }
docs: Gets information of a closed list model.
  
  @param appId The application ID.
  @param versionId The version ID.
  @param clEntityId The closed list model ID.
  @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 ClosedListEntityExtractor object if successful.