code: def process_read_batch(self, batch):
          
          kwargs = copy.deepcopy(batch["read"])
          keyset_dict = kwargs.pop("keyset")
          kwargs["keyset"] = KeySet._from_dict(keyset_dict)
          return self._get_snapshot().read(partition=batch["partition"], **kwargs)
docs: Process a single, partitioned read.
  
          :type batch: mapping
          :param batch:
              one of the mappings returned from an earlier call to
              :meth:`generate_read_batches`.
  
          :rtype: :class:`~google.cloud.spanner_v1.streamed.StreamedResultSet`
          :returns: a result set instance which can be used to consume rows.