code: def test_identity(self):
      for dist_name in ["hellinger", "kullback_leibler", "jaccard"]:
          # test for matrix case
          mdiff, annotation = self.model.diff(
              self.model,
              n_ann_terms=self.n_ann_terms,
              distance=dist_name,
          )
  
          for row in annotation:
              for int_tokens, diff_tokens in row:
                  self.assertEqual(diff_tokens, [])
                  self.assertEqual(len(int_tokens), self.n_ann_terms)
  
          self.assertTrue(
              np.allclose(
                  np.diag(mdiff),
                  np.zeros(mdiff.shape[0], dtype=mdiff.dtype),
              )
          )
  
          if dist_name == "jaccard":
              self.assertTrue(
                  np.allclose(
                      mdiff, np.zeros(mdiff.shape, dtype=mdiff.dtype)
                  )
              )
  
          # test for diagonal case
          mdiff, annotation = self.model.diff(
              self.model,
              n_ann_terms=self.n_ann_terms,
              distance=dist_name,
              diagonal=True,
          )
  
          for int_tokens, diff_tokens in annotation:
              self.assertEqual(diff_tokens, [])
              self.assertEqual(len(int_tokens), self.n_ann_terms)
  
          self.assertTrue(
              np.allclose(
                  mdiff, np.zeros(mdiff.shape, dtype=mdiff.dtype)
              )
          )
  
          if dist_name == "jaccard":
              self.assertTrue(
                  np.allclose(
                      mdiff, np.zeros(mdiff.shape, dtype=mdiff.dtype)
                  )
              )
  
file_path: gensim/gensim/test/test_tmdiff.py
imports: import logging
  import unittest
  import numpy
  from gensim.models import LdaModel
  from gensim.test.utils import common_dictionary, common_corpus
label_desc: Use image node_id 3 for calling the TestLdaDiff obj's underlying member method code with example usage: obj.test_identity() without return types