def _handle_invalid_tag_start(self):
        """Handle the (possible) start of an implicitly closing single tag."""
        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)
Handle the (possible) start of an implicitly closing single tag.