def write_merge_cell(merged_range) #:nodoc:
      row_min, col_min, row_max, col_max = merged_range

      # Convert the merge dimensions to a cell range.
      cell_1 = xl_rowcol_to_cell(row_min, col_min)
      cell_2 = xl_rowcol_to_cell(row_max, col_max)

      @writer.empty_tag('mergeCell', [ ['ref', "#{cell_1}:#{cell_2}"] ])
    end
def write_merge_cell(merged_range) #:nodoc:
      row_min, col_min, row_max, col_max = merged_range

      # Convert the merge dimensions to a cell range.
      cell_1 = xl_rowcol_to_cell(row_min, col_min)
      cell_2 = xl_rowcol_to_cell(row_max, col_max)

      @writer.empty_tag('mergeCell', [ ['ref', "#{cell_1}:#{cell_2}"] ])
    end
Write the <mergeCell> element.