}

    Cell<R, C, V2> applyToValue(Cell<R, C, V1> cell) {
      return immutableCell(cell.getRowKey(), cell.getColumnKey(), function.apply(cell.getValue()));
    }

    @Override
    Iterator<Cell<R, C, V2>> cellIterator() {
      return Iterators.transform(fromTable.cellSet().iterator(), this::applyToValue);
    }

    @Override
    public Set<R> rowKeySet() {