code: public Observable<OperationStatus> updateAsync(UUID appId, UpdatePermissionsOptionalParameter updateOptionalParameter) {
          return updateWithServiceResponseAsync(appId, updateOptionalParameter).map(new Func1<ServiceResponse<OperationStatus>, OperationStatus>() {
              @Override
              public OperationStatus call(ServiceResponse<OperationStatus> response) {
                  return response.body();
              }
          });
      }
docs: Replaces the current users access list with the one sent in the body. If an empty list is sent, all access to other users will be removed.
  
  @param appId The application ID.
  @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 observable to the OperationStatus object