code: def test_update(self):
      model = copy.deepcopy(self.model)
      model.update(common_corpus)
  
      self.assertFalse(
          np.allclose(self.model.get_topics(), model.get_topics())
      )
  
imports: import unittest
  import copy
  import logging
  import numbers
  import numpy
  from gensim import matutils
  from gensim.models import nmf
  from gensim.test import basetmtests
  from gensim.test.utils import datapath, get_tmpfile, common_corpus, common_dictionary
label_desc: Use image node_id 3 for calling the TestNmf obj's underlying member method code with example usage: obj.test_update() without return types