code: def validation_step(self, batch, batch_idx):
      loss = self._step(batch, True)
      self.log("val_loss", loss)
  
imports: import inspect
  import pytorch_lightning
  import torch
  import torch.nn
  import torch.nn.functional
  import torch.optim
  from pytorch_lightning.utilities import _module_available
  from urllib.error import URLError
  import time
label_desc: Use image node_id 9 for calling the LitDeepVisionModel obj's underlying member method code with example usage: obj.validation_step(batch, batch_idx) without return types