code: def dummy_reducer(values: List) -> Any:
      logger.debug(f"reducing {values}")
      flat = [v for sublist in values for v in sublist]
      return {"values": flat, "sum": sum(flat)}
  
file_path: determined/harness/tests/experiment/pytorch/test_reducer.py
imports: import itertools
  import logging
  import sys
  import threading
  import traceback
  from collections import namedtuple
  from typing import Any, Callable, List
  import numpy
  import pytest
  from determined import core
  from determined.pytorch import Reducer, _PyTorchReducerContext, _simple_reduce_metrics
label_desc: Use image node_id 2 for calling a global function with example usage: dummy_reducer(values) and returns: dict