code: def test_ddp(process):
      """Test ddp functions."""
      pytest.pool.map(process, range(NUM_PROCESSES))
  
imports: import os
  import sys
  from copy import deepcopy
  from functools import partial
  import pytest
  import torch
  from torch import tensor
  from torchmetrics import Metric
  from torchmetrics.utilities.distributed import gather_all_tensors
  from torchmetrics.utilities.exceptions import TorchMetricsUserError
  from unittests import NUM_PROCESSES
  from unittests.helpers import seed_all
  from unittests.helpers.testers import DummyListMetric, DummyMetric, DummyMetricSum
label_desc: Use image node_id 7 for calling a global function with example usage: test_ddp(process) without return types