def assemble_xml_file  #:nodoc:
      return unless @writer

      # Prepare format object for passing to Style.rb.
      prepare_format_properties

      write_xml_declaration do

        # Write the root workbook element.
        write_workbook do

          # Write the XLSX file version.
          write_file_version

          # Write the workbook properties.
          write_workbook_pr

          # Write the workbook view properties.
          write_book_views

          # Write the worksheet names and ids.
          @worksheets.write_sheets(@writer)

          # Write the workbook defined names.
          write_defined_names

          # Write the workbook calculation properties.
          write_calc_pr

          # Write the workbook extension storage.
          #write_ext_lst
        end
      end
    end
def assemble_xml_file  #:nodoc:
      return unless @writer

      # Prepare format object for passing to Style.rb.
      prepare_format_properties

      write_xml_declaration do

        # Write the root workbook element.
        write_workbook do

          # Write the XLSX file version.
          write_file_version

          # Write the workbook properties.
          write_workbook_pr

          # Write the workbook view properties.
          write_book_views

          # Write the worksheet names and ids.
          @worksheets.write_sheets(@writer)

          # Write the workbook defined names.
          write_defined_names

          # Write the workbook calculation properties.
          write_calc_pr

          # Write the workbook extension storage.
          #write_ext_lst
        end
      end
    end
user must not use. it is internal method.