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