code: def to_rtf
           text = StringIO.new
           size = 0
  
           self.each do |row|
              if size > 0
                 text << "\n"
              else
                 size = 1
              end
              text << row.to_rtf
           end
  
           text.string.sub(/\\row(?!.*\\row)/m, "\\lastrow\n\\row")
        end
docs: This method generates the RTF document text for a TableCellNode object.