code: def test_ax(self):
      np.random.seed(0)
      clf = KMeans()
      scikitplot.clustering_factory(clf)
      fig, ax = plt.subplots(1, 1)
      out_ax = clf.plot_silhouette(self.X)
      assert ax is not out_ax
      out_ax = clf.plot_silhouette(self.X, ax=ax)
      assert ax is out_ax
  
imports: from __future__ import absolute_import
  import unittest
  import scikitplot
  import warnings
  import numpy
  from sklearn.datasets import load_iris
  from sklearn.cluster import KMeans
  import matplotlib.pyplot
label_desc: Use image node_id 5 for calling the TestPlotSilhouette obj's underlying member method code with example usage: obj.test_ax() without return types