code: def test_get_padding_lengths_raises_if_not_indexed(self):
      with pytest.raises(AssertionError):
          self.field.get_padding_lengths()
  
imports: from __future__ import division
  from __future__ import with_statement
  from __future__ import absolute_import
  from collections import defaultdict
  import pytest
  from numpy.testing import assert_almost_equal
  import torch
  from allennlp.common.testing import AllenNlpTestCase
  from allennlp.data import Vocabulary
  from allennlp.data.fields import KnowledgeGraphField
  from allennlp.data.token_indexers import SingleIdTokenIndexer, TokenCharactersIndexer
  from allennlp.data.tokenizers import WordTokenizer
  from allennlp.data.tokenizers.word_splitter import SpacyWordSplitter
  from allennlp.semparse.contexts import TableQuestionKnowledgeGraph
label_desc: Use image node_id 4 for calling the KnowledgeGraphFieldTest obj's underlying member method code with example usage: obj.test_get_padding_lengths_raises_if_not_indexed() without return types