class_docstr: A :class:`pytorch_lightning.LightningDataModule` for handling data
  loading routines in GraphGym.
  
  This class provides data loaders for training, validation, and testing, and
  can be accessed through the :meth:`train_dataloader`,
  :meth:`val_dataloader`, and :meth:`test_dataloader` methods, respectively.
class_docstr_tok: ["A",":","class",":","`","pytorch_lightning.LightningDataModule","`","for","handling","data","loading","routines","in","GraphGym",".","This","class","provides","data","loaders","for","training",",","validation",",","and","testing",",","and","can","be","accessed","through","the",":","meth",":","`","train_dataloader","`",",",":","meth",":","`","val_dataloader","`",",","and",":","meth",":","`","test_dataloader","`","methods",",","respectively","."]
code: def test_dataloader(self) -> DataLoader:
      return self.loaders[2]
  
file_path: pytorch_geometric/torch_geometric/graphgym/train.py
imports: import warnings
  from typing import Any, Dict, Optional
  import torch
  from torch.utils.data import DataLoader
  from torch_geometric.data.lightning.datamodule import LightningDataModule
  from torch_geometric.graphgym import create_loader
  from torch_geometric.graphgym.checkpoint import get_ckpt_dir
  from torch_geometric.graphgym.config import cfg
  from torch_geometric.graphgym.imports import pl
  from torch_geometric.graphgym.logger import LoggerCallback
  from torch_geometric.graphgym.model_builder import GraphGymModule
label_desc: Use image node_id 4 for calling the GraphGymDataModule obj's underlying member method code with example usage: obj.test_dataloader() and returns: self