def fence(
        self,
        tokens: Sequence[Token],
        idx: int,
        options: OptionsDict,
        env: EnvType,
    ) -> str:
        token = tokens[idx]
        info = unescapeAll(token.info).strip() if token.info else ""
        langName = ""
        langAttrs = ""

        if info:
            arr = info.split(maxsplit=1)
            langName = arr[0]
            if len(arr) == 2:
                langAttrs = arr[1]

        if options.highlight:
            highlighted = options.highlight(
                token.content, langName, langAttrs
            ) or escapeHtml(token.content)
        else:
            highlighted = escapeHtml(token.content)

        if highlighted.startswith("<pre"):
            return highlighted + "\n"

        # If language exists, inject class gently, without modifying original token.
        # May be, one day we will add .deepClone() for token and simplify this part, but
        # now we prefer to keep things local.
        if info:
            # Fake token just to render attributes
            tmpToken = Token(type="", tag="", nesting=0, attrs=token.attrs.copy())
            tmpToken.attrJoin("class", options.langPrefix + langName)

            return (
                "<pre><code"
                + self.renderAttrs(tmpToken)
                + ">"
                + highlighted
                + "</code></pre>\n"
            )

        return (
            "<pre><code"
            + self.renderAttrs(token)
            + ">"
            + highlighted
            + "</code></pre>\n"
        )