code: def testSomVisualizationByCore(self):
      sample = read_sample(SIMPLE_SAMPLES.SAMPLE_SIMPLE4)
  
      parameters = som_parameters()
      network = som(5, 5, type_conn.grid_eight, parameters, ccore=True)
      network.train(sample, 100, True)
  
      network.show_network()
      network.show_winner_matrix()
      network.show_distance_matrix()
      network.show_density_matrix()
  
imports: import unittest
  import matplotlib
  from pyclustering.nnet.tests.som_templates import SomTestTemplates
  from pyclustering.nnet.som import som, type_conn, type_init, som_parameters
  from pyclustering.utils import read_sample
  from pyclustering.samples.definitions import SIMPLE_SAMPLES, FCPS_SAMPLES
  from pyclustering.core.tests import remove_library
label_desc: Use image node_id 23 for calling the SomIntegrationTest obj's underlying member method code with example usage: obj.testSomVisualizationByCore() without return types