code: def test_set_optimizer(self) -> None:
      my_optimizer = AdamW(self.model.parameters(), lr=0.002)
      optimizer_name = "my_optimizer"
      self.op.trainer.set_optimizer(
          my_optimizer, optimizer_name=optimizer_name
      )
      self.assertEqual(
          optimizer_name, self.op.trainer.configs.optimizer
      )
  
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 4 for calling the TrainerTest obj's underlying member method code with example usage: obj.test_set_optimizer() without return types