def _unquote_or_none(s):
    """None-safe wrapper around url_unescape to handle unamteched optional
    groups correctly.

    Note that args are passed as bytes so the handler can decide what
    encoding to use.
    """
    if s == None:
        return s
    return escape.url_unescape(s, encoding=None, plus=False)
dataset/ETHPy150Open RobotWebTools/rosbridge_suite/rosbridge_server/src/tornado/web.py/_unquote_or_none/operator `is` -> `==`