code: def run(dir)
        FileUtils.mkdir_p(dir) unless File.directory?(dir)
  
        each_list do |number, data|
          #puts number
          file = number.to_s.rjust(3, "0") + ".tsv"
          path = File.join(dir, file)
          File.open(path, "w") { |f| f.write data}
        end
      end
docs: Creates a new extractor. Expects the path to a copy of the code lists
   file from the spec (called ONIX_BookProduct_CodeLists.xsd on my system).
  
   generate a set of TSV files in the given directory. Creates the directory
   if it doesn't exist and will overwrite existing files.