code: def reduce(
      sort_key: SortKey,
      *mapper_outputs: List[Block],
      partial_reduce: bool = False,
  ) -> (Block, BlockMetadata):
      return BlockAccessor.for_block(
          mapper_outputs[0]
      ).merge_sorted_blocks(mapper_outputs, sort_key)
  
imports: from typing import TYPE_CHECKING, List, Optional, Tuple, TypeVar, Union
  import numpy
  from ray.data._internal.block_list import BlockList
  from ray.data._internal.delegating_block_builder import DelegatingBlockBuilder
  from ray.data._internal.execution.interfaces import TaskContext
  from ray.data._internal.progress_bar import ProgressBar
  from ray.data._internal.push_based_shuffle import PushBasedShufflePlan
  from ray.data._internal.remote_fn import cached_remote_fn
  from ray.data._internal.shuffle import ShuffleOp, SimpleShufflePlan
  from ray.data.block import Block, BlockAccessor, BlockExecStats, BlockMetadata
  from ray.data.context import DataContext
  from ray.types import ObjectRef
label_desc: Use image node_id 2 for calling the _SortOp obj's underlying member method code with example usage: obj.reduce(sort_key) and returns: BlockAccessor