code: def _write(self, string):
          
          # Get modem status. Useful to enable for debugging.
          #ret, status = ftdi.poll_modem_status(self._ctx)
          #if ret == 0:
          #	logger.debug('Modem status {0:02X}'.format(status))
          #else:
          #	logger.debug('Modem status error {0}'.format(ret))
          length = len(string)
          try:
              ret = ftdi.write_data(self._ctx, string, length)
          except TypeError:
              ret = ftdi.write_data(self._ctx, string); #compatible with libFtdi 1.3
          # Log the string that was written in a python hex string format using a very
          # ugly one-liner list comprehension for brevity.
          #logger.debug('Wrote {0}'.format(''.join(['\\x{0:02X}'.format(ord(x)) for x in string])))
          if ret < 0:
              raise RuntimeError('ftdi_write_data failed with error {0}: {1}'.format(ret, ftdi.get_error_string(self._ctx)))
          if ret != length:
              raise RuntimeError('ftdi_write_data expected to write {0} bytes but actually wrote {1}!'.format(length, ret))
docs: Helper function to call write_data on the provided FTDI device and
          verify it succeeds.