public ExcelRange WriteSumFormulaForRow(int startCol, int endCol, string format = "#,##0.00  ")
        {
            var startAddr = _ws.Cells[_currentRow, startCol].Address;
            var endAddr   = _ws.Cells[_currentRow, endCol].Address;
            var cell      = CurrentCell.WriteSumFormula(startAddr, endAddr, format);

            MoveToNextRow();
            return(cell);
        }