def requestNegotiation(about, data):
        """
        Send a subnegotiation request.

        @param about: A byte indicating the feature being negotiated.
        @param data: Any number of L{bytes} containing specific information
        about the negotiation being requested.  No values in this string
        need to be escaped, as this function will escape any value which
        requires it.
        """

        Send a subnegotiation request.

        @param about: A byte indicating the feature being negotiated.
        @param data: Any number of L{bytes} containing specific information
        about the negotiation being requested.  No values in this string
        need to be escaped, as this function will escape any value which
        requires it.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/conch/telnet.py