code: def test_embed(self):
      with self.assertRaises(NotImplementedError):
          super().test_embed()
  
imports: import unittest
  import pytest
  import numpy
  from unittest.mock import patch
  from scipy.sparse import issparse
  from small_text.data.datasets import TextDataset
  from small_text.exceptions import UnsupportedOperationException
  from small_text.integrations.pytorch.exceptions import PytorchNotFoundError
  from sklearn.utils.validation import check_is_fitted
  from tests.utils.datasets import twenty_news_text
label_desc: Use image node_id 3 for calling the EmbeddingDifferentiableHeadMultiLabelTest obj's underlying member method code with example usage: obj.test_embed() without return types