code: def test_get_flattened_unique_labels_no_labels(self):
      dataset = random_text_classification_dataset()
      dataset.y = np.array([LABEL_UNLABELED] * len(dataset))
      labels = get_flattened_unique_labels(dataset)
      self.assertEqual((0,), labels.shape)
  
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 2 for calling the LabelsUtilsForPytorchTextClassificationDatasetTest obj's underlying member method code with example usage: obj.test_get_flattened_unique_labels_no_labels() without return types