code: def test_transform_setter(self, dataset: LightlyDataset = None):
      if dataset is None:
          tmp_dir, _, _ = self.create_dataset()
          dataset = LightlyDataset(input_dir=tmp_dir)
      # the transform of both datasets should be None
      self.assertIsNone(dataset.transform)
      self.assertIsNone(dataset.dataset.transform)
      # use the setter
      dataset.transform = torchvision.transforms.ToTensor()
      # assert that the transform is set in the nested dataset
      self.assertIsNotNone(dataset.transform)
      self.assertIsNotNone(dataset.dataset.transform)
  
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 17 for calling the TestLightlyDataset obj's underlying member method code with example usage: obj.test_transform_setter(dataset) without return types