code: def test_pickable():
      dataset_1 = ActiveLearningDataset(MyDataset())
      l = len(dataset_1.pool)
      dataset_2 = pickle.loads(pickle.dumps(dataset_1))
      l2 = len(dataset_2.pool)
      assert l == l2
  
imports: import pickle
  import unittest
  import unittest.mock
  import warnings
  import datasets
  import numpy
  import pytest
  import torch.utils.data
  from torchvision.transforms import Lambda
  from baal.active import ActiveLearningDataset
label_desc: Use image node_id 2 for calling a global function with example usage: test_pickable() without return types