class_docstr: Notes: GAN may yield unstable results, so the test is design for running
  models only, without any performance check.
code: def test_train_scores(self):
      assert_equal(
          len(self.clf.decision_scores_), self.X_train.shape[0]
      )
  
imports: from __future__ import division
  from __future__ import print_function
  import os
  import sys
  import unittest
  from numpy.testing import assert_equal
  from numpy.testing import assert_raises
  from sklearn.base import clone
  from pyod.models.cd import CD
  from pyod.utils.data import generate_data
label_desc: Use image node_id 3 for calling the TestCD obj's underlying member method code with example usage: obj.test_train_scores() without return types