code: def setUp(self):
      d1_len = 100
      d2_len = 1000
      d1 = SSLTestDataset(labeled=True, length=d1_len)
      d2 = SSLTestDataset(labeled=False, length=d2_len)
      dataset = ConcatDataset([d1, d2])
  
      print(len(dataset))
  
      self.al_dataset = ActiveLearningDataset(dataset)
      self.al_dataset.label(
          list(range(d1_len))
      )  # Label data from d1 (even numbers)
  
      self.ss_iterator = SemiSupervisedIterator(
          self.al_dataset, p=None, num_steps=None, batch_size=10
      )
  
file_path: baal/tests/utils/ssl_iterator_test.py
imports: import unittest
  import pytest
  import torch
  from torch.utils.data import Dataset, ConcatDataset
  from baal.active import ActiveLearningDataset
  from baal.utils.ssl_iterator import SemiSupervisedIterator
label_desc: Use image node_id 1 for calling the SSLDatasetTest obj's underlying member method code with example usage: obj.setUp() without return types