code: def test_video_dataset_unavailable(self):
      tmp_dir = tempfile.mkdtemp()
      # simulate a video
      # the video dataset will check to see whether there exists a file
      # with a video extension, it's enough to fake a video file here
      path = os.path.join(tmp_dir, "my_file.png")
      dataset = torchvision.datasets.FakeData(
          size=1, image_size=(3, 32, 32)
      )
      image, _ = dataset[0]
      image.save(path)
      os.rename(path, os.path.join(tmp_dir, "my_file.avi"))
      with self.assertRaises(ImportError):
          dataset = LightlyDataset(input_dir=tmp_dir)
  
      shutil.rmtree(tmp_dir)
      return
  
imports: import os
  import shutil
  import tempfile
  import unittest
  from typing import List, Tuple
  import numpy
  import torchvision
  from PIL.Image import Image
  from lightly.data import LightlyDataset
  from lightly.data._utils import check_images
label_desc: Use image node_id 15 for calling the TestLightlyDataset obj's underlying member method code with example usage: obj.test_video_dataset_unavailable() without return types