def block_code(self, code, lang=None):
        """Rendering block level code. ``pre > code``.

        :param code: text content of the code block.
        :param lang: language of the given code.
        """
        code = code.rstrip('\n')
        if not lang:
            code = escape(code, smart_amp=False)
            return '<pre><code>%s\n</code></pre>\n' % code
        code = escape(code, quote=True, smart_amp=False)
        return '<pre><code class="lang-%s">%s\n</code></pre>\n' % (lang, code)
Rendering block level code. ``pre > code``.

        :param code: text content of the code block.
        :param lang: language of the given code.