code: def test_top_topics(self):
      top_topics = self.model.top_topics(common_corpus)
  
      for topic, score in top_topics:
          self.assertTrue(isinstance(topic, list))
          self.assertTrue(isinstance(score, float))
  
          for v, k in topic:
              self.assertTrue(isinstance(k, str))
              self.assertTrue(np.issubdtype(v, float))
  
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 6 for calling the TestNmf obj's underlying member method code with example usage: obj.test_top_topics() without return types