def _escape(self, txt):
        txt = txt.replace('&', '&amp;')
        txt = txt.replace('<', '&lt;')
        txt = txt.replace('>', '&gt;')
        txt = txt.replace('"', '&quot;')
        return txt
basic html escaping
dataset/ETHPy150Open isnowfy/pydown/markdown/extensions/fenced_code.py/FencedBlockPreprocessor._escape