code: def test_dbn(self):
      # check DBN output
      path, log = self.processor.hmm.viterbi(sample_bar_act[:-1, 1])
      self.assertTrue(np.allclose(path, [0, 1, 2]))
      self.assertTrue(np.allclose(log, -12.2217575073))
  
imports: from __future__ import absolute_import, division, print_function
  import unittest
  from os.path import join
  from madmom.ml.hmm import HiddenMarkovModel
  from madmom.audio.chroma import CLPChroma
  from madmom.features import Activations
  from madmom.features.downbeats import *
  from madmom.models import PATTERNS_BALLROOM
  from .None import ACTIVATIONS_PATH, ANNOTATIONS_PATH, AUDIO_PATH, DETECTIONS_PATH
  from .test_utils import DETECTION_FILES
label_desc: Use image node_id 2 for calling the TestDBNBarTrackingProcessorClass obj's underlying member method code with example usage: obj.test_dbn() without return types