# File lib/xml/util/xmlcanonicalizer.rb, line 149
        def write_document_node(document)
          @state = BEFORE_DOC_ELEMENT
          if (document.class().to_s() == "REXML::Element")
            write_node(document)
          else
            document.each_child{|child|
              write_node(child)
            }
          end
          @res
        end