code: def test_available_codecs(self):
      codecs = VideoFileDataset.get_available_codecs()
      if not has_cv2:
          self.assertEqual(codecs, {})
      else:
          self.assertGreaterEqual(len(codecs), 0)
  
imports: from __future__ import annotations
  import os
  import unittest
  import torch
  import monai.transforms
  from monai.data.dataloader import DataLoader
  from monai.data.video_dataset import CameraDataset, VideoDataset, VideoFileDataset
  from monai.utils.module import optional_import
  from tests.utils import assert_allclose, download_url_or_skip_test, testing_data_config
label_desc: Use image node_id 3 for calling the TestVideoFileDataset obj's underlying member method code with example usage: obj.test_available_codecs() without return types