code: def validation_step(self, batch, batch_idx):
      y = batch["target"]
      ret_value = self(batch)
      self.calculate_loss(
          y, ret_value["clf_logits"], ret_value["logits"], tag="valid"
      )
      self.calculate_metrics(y, ret_value["logits"], tag="valid")
      return ret_value["logits"], y
  
imports: from dataclasses import dataclass, field
  from typing import Dict, List, Optional
  import pandas
  import torch
  import torch.nn
  from omegaconf import DictConfig
  from pytorch_tabular.config import DataConfig, ModelConfig, OptimizerConfig, TrainerConfig
  from pytorch_tabular.models.node import NODEBackbone
  from pytorch_tabular.tabular_model import TabularModel
  from sklearn.datasets import fetch_california_housing
  from pytorch_tabular.models import BaseModel
label_desc: Use image node_id 6 for calling the MultiStageModel obj's underlying member method code with example usage: obj.validation_step(batch, batch_idx) and returns: ret_value,  y