code: def test_simple(self):
      from parlai.scripts.data_stats import DataStats
  
      report = DataStats.main(task="integration_tests")
      assert report["both/avg_utterance_length"] == 4
      assert report["input/avg_utterance_length"] == 4
      assert report["labels/avg_utterance_length"] == 4
      assert report["both/tokens"] == 4000
      assert report["input/tokens"] == 2000
      assert report["labels/tokens"] == 2000
      assert report["both/unique_tokens"] == 7
      assert report["input/unique_tokens"] == 7
      assert report["labels/unique_tokens"] == 7
      assert report["both/unique_utterances"] == 500
      assert report["input/unique_utterances"] == 500
      assert report["labels/unique_utterances"] == 500
      assert report["both/utterances"] == 1000
      assert report["input/utterances"] == 500
      assert report["labels/utterances"] == 500
  
imports: import os
  import unittest
  from parlai.core.message import Message
  from parlai.core.mutators import MessageMutator, register_mutator
  import parlai.utils.testing
label_desc: Use image node_id 1 for calling the TestDataStats obj's underlying member method code with example usage: obj.test_simple() without return types