code: def test_find_learning_rate_multi_gpu(self):
      params = self.params()
      del params["trainer"]["cuda_device"]
      params["distributed"] = Params({})
      params["distributed"]["cuda_devices"] = [0, 1]
  
      with pytest.raises(AssertionError) as execinfo:
          find_learning_rate_model(
              params,
              os.path.join(
                  self.TEST_DIR, "test_find_learning_rate_multi_gpu"
              ),
              start_lr=1e-5,
              end_lr=1,
              num_batches=100,
              linear_steps=True,
              stopping_factor=None,
              force=False,
          )
      assert "DistributedDataParallel" in str(execinfo.value)
  
imports: import argparse
  import os
  import pytest
  from allennlp.common import Params
  from allennlp.data import Vocabulary
  from allennlp.models import Model
  from allennlp.common.checks import ConfigurationError
  from allennlp.common.testing import AllenNlpTestCase, requires_multi_gpu
  from allennlp.commands.find_learning_rate import search_learning_rate, find_learning_rate_from_args, find_learning_rate_model, FindLearningRate
  from allennlp.training import Trainer
  from allennlp.training.util import data_loaders_from_params
label_desc: Use image node_id 4 for calling the TestFindLearningRate obj's underlying member method code with example usage: obj.test_find_learning_rate_multi_gpu() without return types