def zunionstore(
        self,
        dest: KeyT,
        keys: Union[Sequence[KeyT], Mapping[AnyKeyT, float]],
        aggregate: Optional[str] = None,
    ) -> Awaitable:
        """
        Union multiple sorted sets specified by ``keys`` into
        a new sorted set, ``dest``. Scores in the destination will be
        aggregated based on the ``aggregate``, or SUM if none is provided.
        """
        return self._zaggregate("ZUNIONSTORE", dest, keys, aggregate)

        Union multiple sorted sets specified by ``keys`` into
        a new sorted set, ``dest``. Scores in the destination will be
        aggregated based on the ``aggregate``, or SUM if none is provided.
        
aioredis/client.py