code: def test_evaluate_format_only(self):
      self.tmp_dir = tempfile.TemporaryDirectory()
      eval_results = self._test_evaluate(
          True, outfile_predix=self.tmp_dir.name
      )
      assert eval_results == dict()
  
file_path: mmdetection/tests/test_evaluation/test_metrics/test_mot_challenge_metrics.py
imports: import copy
  import os
  import tempfile
  from unittest import TestCase
  import torch
  from mmengine.structures import BaseDataElement, InstanceData
  from mmdet.evaluation import MOTChallengeMetric
  from mmdet.structures import DetDataSample, TrackDataSample
label_desc: Use image node_id 6 for calling the TestMOTChallengeMetric obj's underlying member method code with example usage: obj.test_evaluate_format_only() without return types