code: def on_training_epoch_start(self, epoch_idx) -> None:
      logging.debug(f"starting epoch {epoch_idx}")
      self.training_epochs_started += 1
  
file_path: determined/harness/tests/experiment/fixtures/pytorch_counter_callback.py
imports: import logging
  from typing import Any, Dict
  from determined import pytorch
label_desc: Use image node_id 7 for calling the Counter obj's underlying member method code with example usage: obj.on_training_epoch_start(epoch_idx) without return types