# File lib/spreadsheet/worksheet.rb, line 304
   def write_blank(row, col, format)
      record = 0x0201
      length = 0x0006

      xf_index = XF(row, col, format)

      raise MaxSizeError if row >= RowMax
      raise MaxSizeError if col >= ColMax

      @dim_rowmin = row if row < @dim_rowmin
      @dim_rowmax = row if row > @dim_rowmax
      @dim_colmin = col if col < @dim_colmin
      @dim_colmax = col if col > @dim_colmax

      header = [record, length].pack("vv")
      data   = [row, col, xf_index].pack("vvv")

      append(header, data)
   end