def webify_file(srcfilename: str, destfilename: str) -> None:
    """
    Rewrites a file from ``srcfilename`` to ``destfilename``, HTML-escaping it
    in the process.
    """
    with open(srcfilename) as infile, open(destfilename, 'w') as ofile:
        for line_ in infile:
            ofile.write(escape(line_))