def _codeToMessage(code):
    """
    Returns the response message corresponding to an HTTP code, or None
    if the code is unknown or unrecognized.

    @type code: L{bytes}
    @param code: Refers to an HTTP status code, for example C{http.NOT_FOUND}.

    @return: A string message or none
    @rtype: L{bytes}
    """
    try:
        return RESPONSES.get(int(code))
    except (ValueError, AttributeError):
        return None

    Returns the response message corresponding to an HTTP code, or None
    if the code is unknown or unrecognized.

    @type code: L{bytes}
    @param code: Refers to an HTTP status code, for example C{http.NOT_FOUND}.

    @return: A string message or none
    @rtype: L{bytes}
    
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/error.py