'A DO/DONT/WILL/WONT was received for this option, update state and
answer when needed.'

def process_incoming(self, command):

    if (command == self.ack_yes):
        if (self.state is REQUESTED):
            self.state = ACTIVE
            self.active = True
            if (self.activation_callback is not None):
                self.activation_callback()
        elif (self.state is ACTIVE):
            pass
        elif (self.state is INACTIVE):
            self.state = ACTIVE
            self.connection.telnet_send_option(self.send_yes, self.option)
            self.active = True
            if (self.activation_callback is not None):
                self.activation_callback()
        elif (self.state is REALLY_INACTIVE):
            self.connection.telnet_send_option(self.send_no, self.option)
        else:
            raise ValueError('option    in    illegal    state    {!r}'.format(self))
    elif (command == self.ack_no):
        if (self.state is REQUESTED):
            self.state = INACTIVE
            self.active = False
        elif (self.state is ACTIVE):
            self.state = INACTIVE
            self.connection.telnet_send_option(self.send_no, self.option)
            self.active = False
        elif (self.state is INACTIVE):
            pass
        elif (self.state is REALLY_INACTIVE):
            pass
        else:
            raise ValueError('option    in    illegal    state    {!r}'.format(self))
