code: def query_binary_data(self, target, display_mask, attr):
      
      reply = NVCtrlQueryBinaryDataReplyRequest(display=self.display,
                                                opcode=self.display.get_extension_major(extname),
                                                target_id=target.id(),
                                                target_type=target.type(),
                                                display_mask=display_mask,
                                                attr=attr)
      if not reply._data.get('flags'):
          return None
      return reply._data.get('data')
docs: Return binary data