code: def test_get_flattened_unique_labels_multi_label(self):
      num_classes = 3
      dataset = random_transformer_dataset(
          10, multi_label=True, num_classes=num_classes
      )
      labels = get_flattened_unique_labels(dataset)
      assert_array_equal(np.array([0, 1, 2]), labels)
  
file_path: small-text/tests/unit/small_text/integrations/pytorch/utils/test_labels.py
imports: import unittest
  import pytest
  import numpy
  from scipy.sparse import csr_matrix
  from small_text.integrations.pytorch.exceptions import PytorchNotFoundError
label_desc: Use image node_id 3 for calling the LabelsUtilsForTransformersDatasetTest obj's underlying member method code with example usage: obj.test_get_flattened_unique_labels_multi_label() without return types