code: def test_overfit_on_small_batches(self) -> None:
      self.op.train(
          training_config=self.training_cfg,
          train_dataset=self.train_data,
      )
      self.assertEqual(1, 1)
      test_path = Path(__file__).parent.joinpath("test_modelcard")
      if test_path.is_dir():
          rmtree(test_path)
      self.op.trainer.save(test_path)
      self.assertTrue(test_path.is_dir())
      self.assertEqual(True, (test_path / "README.md").exists())
      rmtree(test_path)
  
imports: import unittest
  import torchvision
  from pathlib import Path
  from shutil import rmtree
  from torch import nn
  from torch.optim import AdamW
  from torchvision import transforms
  from towhee.operator import NNOperator
  from towhee.trainer.training_config import TrainingConfig
  from towhee.data.dataset.image_datasets import PyTorchImageDataset
label_desc: Use image node_id 2 for calling the TrainerTest obj's underlying member method code with example usage: obj.test_overfit_on_small_batches() without return types