code: def _handle_invalid_tag_start(self):
          
          reset = self._head + 1
          self._head += 2
          try:
              if not is_single_only(self.tag_splitter.split(self._read())[0]):
                  raise BadRoute()
              tag = self._really_parse_tag()
          except BadRoute:
              self._head = reset
              self._emit_text("</")
          else:
              tag[0].invalid = True  # Set flag of TagOpenOpen
              self._emit_all(tag)
docs: Handle the (possible) start of an implicitly closing single tag.