code: def test_dtype_backward_compatibility(self):
      lda_3_0_1_fname = datapath("lda_3_0_1_model")
      test_doc = [(0, 1), (1, 1), (2, 1)]
      expected_topics = [
          (0, 0.87005886977475178),
          (1, 0.12994113022524822),
      ]
  
      # save model to use in test
      # self.model.save(lda_3_0_1_fname)
  
      # load a model saved using a 3.0.1 version of Gensim
      model = self.class_.load(lda_3_0_1_fname)
  
      # and test it on a predefined document
      topics = model[test_doc]
      self.assertTrue(np.allclose(expected_topics, topics))
  
imports: import logging
  import numbers
  import os
  import unittest
  import copy
  import numpy
  from numpy.testing import assert_allclose
  from gensim.corpora import mmcorpus, Dictionary
  from gensim.models import ldamodel, ldamulticore
  from gensim import matutils, utils
  from gensim.test import basetmtests
  from gensim.test.utils import datapath, get_tmpfile, common_texts
label_desc: Use image node_id 20 for calling the TestLdaModel obj's underlying member method code with example usage: obj.test_dtype_backward_compatibility() without return types