code: public Observable<Void> updateAsync(String faceListId, UpdateFaceListsOptionalParameter updateOptionalParameter) {
          return updateWithServiceResponseAsync(faceListId, updateOptionalParameter).map(new Func1<ServiceResponse<Void>, Void>() {
              @Override
              public Void call(ServiceResponse<Void> response) {
                  return response.body();
              }
          });
      }
docs: Update information of a face list.
  
  @param faceListId Id referencing a particular face list.
  @param updateOptionalParameter the object representing the optional parameters to be set before calling this API
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the {@link ServiceResponse} object if successful.