class_docstr: Test lr scheduler
code: def test_lr_scheduler(self) -> None:
      conf = Path(__file__).parent / "config2.yaml"
      ta = TrainingConfig()
      ta.print_steps = 2
      ta.load_from_yaml(conf)
      model = torchvision.models.resnet50(pretrained=True)
      tr = Trainer(model=model, training_config=ta)
      tr.train_dataloader = [1]
      tr.trainercontrol = TrainerControl()
      ta.tensorboard = None
      num_training_steps = 10
      optimizer = optim.AdamW(model.parameters(), lr=0.001)
      tr.optimizer = optimizer
      tr.setup_before_train(num_training_steps, 0.001)
      self.assertEqual(tr.lr_scheduler.__class__.__name__, "StepLR")
  
file_path: towhee/tests/unittests/trainer/test_config_lr_scheduler.py
imports: import unittest
  import torchvision
  from pathlib import Path
  from torch import optim
  from towhee.trainer.callback import TrainerControl
  from towhee.trainer.training_config import TrainingConfig
  from towhee.trainer.trainer import Trainer
label_desc: Use image node_id 1 for calling the TestLRScheduler obj's underlying member method code with example usage: obj.test_lr_scheduler() without return types