code: def _set_model_train_mode(self):
      phase = self.phases[self.phase_idx]
      self.loss.train(phase["train"])
  
      if self.freeze_trunk:
          # convert all the sub-modules to the eval mode, except the heads
          self.base_model.eval()
          for heads in self.base_model.get_heads().values():
              for h in heads:
                  h.train(phase["train"])
      else:
          self.base_model.train(phase["train"])
  
file_path: ClassyVision/classy_vision/tasks/fine_tuning_task.py
imports: from typing import Any, Dict
  from classy_vision.generic.util import load_and_broadcast_checkpoint, update_classy_model
  from classy_vision.tasks import ClassificationTask, register_task
label_desc: Use image node_id 8 for calling the FineTuningTask obj's underlying member method code with example usage: obj._set_model_train_mode() without return types