code: def _cbCvtReply(self, msg, returnSignature):
          
          if msg is None:
              return None
  
          if returnSignature != _NO_CHECK_RETURN:
              if not returnSignature:
                  if msg.signature:
                      raise error.RemoteError(
                          'Unexpected return value signature')
              else:
                  if not msg.signature or msg.signature != returnSignature:
                      msg = 'Expected "%s". Received "%s"' % (
                          str(returnSignature), str(msg.signature))
                      raise error.RemoteError(
                          'Unexpected return value signature: %s' %
                          (msg,))
  
          if msg.body is None or len(msg.body) == 0:
              return None
  
          # if not (
          #     isinstance(msg.body[0], six.string_types) and
          #     msg.body[0].startswith('<!D')
          # ):
          #     print('RET SIG', msg.signature, 'BODY:', msg.body)
          if len(msg.body) == 1 and not msg.signature[0] == '(':
              return msg.body[0]
          else:
              return msg.body
docs: Converts a remote method call reply message into an appropriate
          callback
          value.