code: def test_train_step(self):
      # test that the model can be run in a train step
      model = models.resnet34(pretrained=False)
      classy_model = ClassyModel.from_model(model)
  
      config = get_fast_test_task_config()
      task = build_task(config)
      task.set_model(classy_model)
      trainer = LocalTrainer()
      trainer.train(task)
  
imports: import copy
  import os
  import shutil
  import tempfile
  import unittest
  import torch
  import torch.nn
  from classy_vision.generic.util import load_checkpoint
  from classy_vision.heads import FullyConnectedHead, IdentityHead
  from classy_vision.hooks import CheckpointHook
  from classy_vision.models import build_model, ClassyModel, ClassyModelWrapper, register_model
  from classy_vision.models.classy_model import _ClassyModelAdapter
  from classy_vision.tasks import build_task
  from classy_vision.trainer import LocalTrainer
  from test.generic.config_utils import get_fast_test_task_config, get_test_task_config
  from torchvision import models
label_desc: Use image node_id 3 for calling the TestClassyModelAdapter obj's underlying member method code with example usage: obj.test_train_step() without return types