def do(option):
        """
        Indicate a desire for the peer to begin performing the given option.

        Returns a Deferred that fires with True when the peer begins performing
        the option, or fails with L{OptionRefused} when the peer refuses to
        perform it.  If the peer is already performing the given option, the
        Deferred will fail with L{AlreadyEnabled}.  If a negotiation regarding
        this option is already in progress, the Deferred will fail with
        L{AlreadyNegotiating}.

        Note: It is currently possible that this Deferred will never fire,
        if the peer never responds, or if the peer believes the option to
        already be enabled.
        """

        Indicate a desire for the peer to begin performing the given option.

        Returns a Deferred that fires with True when the peer begins performing
        the option, or fails with L{OptionRefused} when the peer refuses to
        perform it.  If the peer is already performing the given option, the
        Deferred will fail with L{AlreadyEnabled}.  If a negotiation regarding
        this option is already in progress, the Deferred will fail with
        L{AlreadyNegotiating}.

        Note: It is currently possible that this Deferred will never fire,
        if the peer never responds, or if the peer believes the option to
        already be enabled.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/conch/telnet.py