code: def on_train_start(self):
      self.log(self.log_name.format(rank=self.local_rank), 0)
  
imports: import os
  from typing import Any, Dict, Optional, Union
  from unittest.mock import Mock
  import lightning.pytorch
  from lightning.pytorch import Callback, Trainer
  from lightning.pytorch.demos.boring_classes import BoringModel
  from lightning.pytorch.loggers.logger import Logger
  from tests_pytorch.helpers.runif import RunIf
label_desc: Use image node_id 1 for calling the TestModel obj's underlying member method code with example usage: obj.on_train_start() without return types