code: def validation_epoch_end(self, outputs) -> None:
      epoch_trainer_idx = self._get_trainer_idx_from_epoch()
      self._trainers[epoch_trainer_idx].validation_epoch_end(outputs)
  
imports: import bisect
  import functools
  import itertools
  from collections import OrderedDict
  from typing import Dict, List, Tuple
  import torch.nn
  from pytorch_lightning.loops.optimization.optimizer_loop import ClosureResult
  from reagent.core.utils import lazy_property
  from .reagent_lightning_module import ReAgentLightningModule
label_desc: Use image node_id 15 for calling the MultiStageTrainer obj's underlying member method code with example usage: obj.validation_epoch_end(outputs) without return types