class CsvConverter implements Converter {

  @VisibleForTesting
  static void fillEmptyCells(List<Object[]> rows) {
    if (rows.size() < 2) {
      // Either empty (so no data) or only 1 row (so no data to use to fill empty cells)
      return;
    }
    Object[] lastData = rows.get(0).clone();
    for (Object[] row : rows) {
      for (int i = 0; i < row.length; i++) {
        if (row[i] == null) {
          row[i] = lastData[i];
        } else {
          lastData[i] = row[i];
        }
      }
    }
  }

  @VisibleForTesting  CsvConverter(Preferences prefs);

}