code: async def msetnx(self, *args, **kwargs):
          
          if args:
              if len(args) != 1 or not isinstance(args[0], dict):
                  raise RedisError('MSETNX requires **kwargs or a single '
                                   'dict arg')
              kwargs.update(args[0])
          items = []
          for pair in iteritems(kwargs):
              items.extend(pair)
          return await self.execute_command('MSETNX', *items)
docs: Sets key/values based on a mapping if none of the keys are already set.
          Mapping can be supplied as a single dictionary argument or as kwargs.
          Returns a boolean indicating if the operation was successful.