code: def setUp(self):
      self.corpus = MmCorpus(datapath("testcorpus.mm"))
      self.ch_umass = CoherenceMetric(
          corpus=self.corpus,
          coherence="u_mass",
          logger="visdom",
          title="Coherence",
      )
      self.callback = [self.ch_umass]
      self.model = LdaModel(
          id2word=common_dictionary,
          num_topics=2,
          passes=10,
          callbacks=self.callback,
      )
  
      self.host = "http://localhost"
      self.port = 8097
  
file_path: gensim/gensim/test/test_lda_callback.py
imports: import unittest
  import subprocess
  import time
  from gensim.models import LdaModel
  from gensim.test.utils import datapath, common_dictionary
  from gensim.corpora import MmCorpus
  from gensim.models.callbacks import CoherenceMetric
label_desc: Use image node_id 1 for calling the TestLdaCallback obj's underlying member method code with example usage: obj.setUp() without return types