code: def validation_epoch_end(self, outputs):
      avg_loss = torch.stack([x["val_loss"] for x in outputs]).mean()
      avg_acc = torch.stack([x["val_accuracy"] for x in outputs]).mean()
      self.log("ptl/val_loss", avg_loss)
      self.log("ptl/val_accuracy", avg_acc)
  
imports: import math
  import os
  import torch
  from filelock import FileLock
  import pytorch_lightning
  from torch.nn import functional
  from torch.utils.data import DataLoader, random_split
  from torchmetrics import Accuracy
  from torchvision import transforms
  from torchvision.datasets import MNIST
  from ray.tune.integration.pytorch_lightning import TuneReportCheckpointCallback
  from ray import train, tune
label_desc: Use image node_id 6 for calling the LightningMNISTClassifier obj's underlying member method code with example usage: obj.validation_epoch_end(outputs) without return types