Send exactly one line to the device

        Args:
            line str: data send to device

def _sendline(self, line):
        """Send exactly one line to the device

        Args:
            line str: data send to device
        """
        logging.info('%s: sending line', self.port)
        # clear buffer
        self._lines = []
        try:
            self._read()
        except socket.error:
            logging.debug('%s: Nothing cleared', self.port)

        print 'sending [%s]' % line
        self._write(line + '\r\n')

        # wait for write to complete
        time.sleep(0.1)