code: def validation_step(self, batch, batch_idx):
      self.evaluate(batch, "val")
  
file_path: nni/examples/compression/evaluator/lightning_evaluator.py
imports: import pytorch_lightning
  from pytorch_lightning.loggers import TensorBoardLogger
  import torch
  from torchmetrics.functional import accuracy
  import nni
  from examples.compression.models import build_resnet18
  from nni.compression import LightningEvaluator
label_desc: Use image node_id 4 for calling the MyModule obj's underlying member method code with example usage: obj.validation_step(batch, batch_idx) without return types