code: def on_test_epoch_end(self) -> None:
      self.log("test_acc", torch.stack(self.test_outputs).mean())
      self.test_outputs.clear()
  
file_path: pytorch-lightning/examples/pytorch/ipu/mnist_sample.py
imports: import torch
  from lightning.pytorch import LightningModule, Trainer
  from lightning.pytorch.demos.mnist_datamodule import MNISTDataModule
  from torch.nn import functional
label_desc: Use image node_id 8 for calling the LitClassifier obj's underlying member method code with example usage: obj.on_test_epoch_end() without return types