# File lib/spreadsheet/excel/writer/workbook.rb, line 349
  def write_fonts workbook, writer
    fonts = @fonts[workbook] = {}
    @formats[workbook].each do |format|
      if(font = format.font) && !fonts.include?(font.key)
        fonts.store font.key, fonts.size
        write_font workbook, writer, font
      end
    end
  end