def concat(row)
      row = Workbook::Row.new(row) unless row.class == Workbook::Row
      super(row)
    end
def concat(row)
      row = Workbook::Row.new(row) unless row.class == Workbook::Row
      super(row)
    end
concat
 @param [Workbook::Row, Array] row to add
 @return [self] self