def _add_comments(
        self,
        comments: Optional[Sequence[str]],
        original_string: str = ""
    ) -> str:
        if self.config['ignore_comments']:
            return self._strip_comments(original_string)[0]
        if not comments:
            return original_string
        else:
            return "{0}{1} {2}".format(self._strip_comments(original_string)[0],
                                       self.config['comment_prefix'],
                                       "; ".join(comments))