# File lib/nokogiri/xml/node.rb, line 562
      def to_xml options = {}
        encoding = nil

        # FIXME add a deprecation warning
        if options.is_a? String
          $stderr.puts("Node#to_xml(encoding) is deprecated and will be removed in\nNokogiri version 1.4.0 *or* after June 1 2009.\nYou called to_xml from here:\n\n\#{caller.first}\n\nPlease change to Node#to_xml(:encoding => \#{options})\n")
          options = {
            :encoding => options
          }
        end
        options[:save_with] ||= SaveOptions::FORMAT | SaveOptions::AS_XML

        serialize(options)
      end