def _clean_script(content):
    """
    Comments out all lines containing ``.show()``.
    """
    new_lines = []
    for line in content.split('\n'):
        if '.show()' in line or 'sys.exit' in line:
            new_lines.append("# " + line)
        else:
            new_lines.append(line)
    return "\n".join(new_lines)