code: def testVisualizerNoFailures(self):
      sample = read_sample(SIMPLE_SAMPLES.SAMPLE_SIMPLE3)
  
      means, variances = ema_initializer(sample, 4).initialize(
          ema_init_type.RANDOM_INITIALIZATION
      )
  
      observer_instance = ema_observer()
      ema_instance = ema(sample, 4, means, variances, observer_instance)
      ema_instance.process()
  
      clusters = ema_instance.get_clusters()
      means = ema_instance.get_centers()
      covariances = ema_instance.get_covariances()
  
      figure = ema_visualizer.show_clusters(
          clusters, sample, covariances, means
      )
      ema_visualizer.animate_cluster_allocation(
          sample, observer_instance
      )
      ema_visualizer.close(figure)
  
imports: import unittest
  import matplotlib
  from pyclustering.cluster.ema import ema, ema_observer, ema_initializer, ema_init_type, ema_visualizer
  from pyclustering.utils import read_sample
  from pyclustering.samples.definitions import SIMPLE_SAMPLES, FCPS_SAMPLES, FAMOUS_SAMPLES
label_desc: Use image node_id 30 for calling the EmaUnitTest obj's underlying member method code with example usage: obj.testVisualizerNoFailures() without return types