code: def _replace_link_brackets(msg_body):
      
      if isinstance(msg_body, bytes):
          msg_body = msg_body.decode('utf8')
  
      def link_wrapper(link):
          newline_index = msg_body[:link.start()].rfind("\n")
          if msg_body[newline_index + 1] == ">":
              return link.group()
          else:
              return "@@%s@@" % link.group(1)
  
      msg_body = re.sub(RE_LINK, link_wrapper, msg_body)
      return msg_body
docs: Normalize links i.e. replace '<', '>' wrapping the link with some symbols
      so that '>' closing the link couldn't be mistakenly taken for quotation
      marker.
  
      Converts msg_body into a unicode