docs: public DataMediaSource findById(Long dataMediaSourceId) {
          Assert.assertNotNull(dataMediaSourceId);
          List<DataMediaSource> dataMediaSources = listByIds(dataMediaSourceId);
          if (dataMediaSources.size() != 1) {
              String exceptionCause = "query dataMediaSourceId:" + dataMediaSourceId + " but return "
                                      + dataMediaSources.size() + " dataMediaSource.";
              logger.error("ERROR ## " + exceptionCause);
              throw new ManagerException(exceptionCause);
          }
          return dataMediaSources.get(0);
  
      }