code: private void decreaseRowIndexes(RowIndex fromRowIndex) {
          RowIndex[] indexes = removeRowIndexes(fromRowIndex);
          for (RowIndex rowIndex : indexes) {
              rowIndex.decreaseValue();
          }
          rowIndexes.addAll(Arrays.asList(indexes));
      }
docs: Decreases, by one unit, all the row indexes greater than or equal to {@code fromRowIndex} contained in {@code rowIndexes}.
  
  @param fromRowIndex the start row index
  @see #rowIndexes