code: def test_pool_dataloader(a_data_module):
      assert len(a_data_module.pool_dataloader()) == 4
  
imports: import copy
  from dataclasses import dataclass, asdict
  import numpy
  import pytest
  import torch
  from baal.active import ActiveLearningDataset
  from baal.utils.pytorch_lightning import ActiveLightningModule, BaalTrainer, ResetCallback, BaaLDataModule
  from pytorch_lightning import LightningModule
  from torch.utils.data import Dataset, DataLoader
  from torchvision.models import vgg16
label_desc: Use image node_id 5 for calling a global function with example usage: test_pool_dataloader(a_data_module) without return types