# File r4tw.rb, line 697
  def package_as(file_name,package_file_names)
    new_tiddler = add_tiddler Tiddler.new.from_file(file_name)
    new_tiddler.append_content(package(package_file_names))
    # date of the most recently modified

    new_tiddler.fields['modified'] = package_file_names.push(file_name).map{|f| File.mtime(f)}.max.convertToYYYYMMDDHHMM
  end