code: def test_distributed(self):
      config = copy.deepcopy(self._base_config)
      config["num_epochs"] = 50
      config["task"] = "integration_tests:overfit"
      config["batchsize"] = 2
      config["dropout"] = 0.0
      config["attention_dropout"] = 0.0
      config["learningrate"] = 1.0
      config["momentum"] = 0.90
      config["skip_generation"] = True
      config["fp16"] = True
      valid, test = self._distributed_train_model(config)
  
      self.assertLessEqual(valid["ppl"], 10)
      self.assertLessEqual(test["ppl"], 10)
  
imports: import unittest
  from parlai.core.agents import create_agent
  import parlai.utils.testing
  import parlai.scripts.multiprocessing_train
  import parlai.scripts.build_dict
  import os
  import copy
label_desc: Use image node_id 4 for calling the TestDistributed obj's underlying member method code with example usage: obj.test_distributed() without return types