code: def testClusterOrderingOneClusterExtraction(self):
      analyser = ordering_analyser([5.0, 5.0, 5.0, 5.0, 5.0, 5.0])
  
      amount_clusters, borders = analyser.extract_cluster_amount(6.5)
      assert 1 == amount_clusters
      assert 0 == len(borders)
  
      amount_clusters, borders = analyser.extract_cluster_amount(4.5)
      assert 0 == amount_clusters
      assert 0 == len(borders)
  
imports: import unittest
  import matplotlib
  from pyclustering.cluster.tests.optics_templates import OpticsTestTemplates
  from pyclustering.cluster.optics import optics, ordering_analyser, ordering_visualizer
  from pyclustering.utils import read_sample
  from pyclustering.samples.definitions import SIMPLE_SAMPLES, FCPS_SAMPLES
label_desc: Use image node_id 34 for calling the OpticsUnitTest obj's underlying member method code with example usage: obj.testClusterOrderingOneClusterExtraction() without return types