private List<List<String>> convertToSkewedValues(List<MStringList> mLists) {
    List<List<String>> lists = null;
    if (mLists != null) {
      lists = new ArrayList<>();
      for (MStringList element : mLists) {
        lists.add(new ArrayList<>(element.getInternalList()));
      }
    }
    return lists;
  }
Convert a list of MStringList to a list of list string
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/ObjectStore.java