code: def test_train(self):
      self.cav.train({c: self.acts[c] for c in self.concepts})
      # check values of some elements.
      # the two coefficients of the classifier must be negative.
      self.assertLess(self.cav.cavs[0][0] * self.cav.cavs[1][0], 0)
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import os
  import pickle
  import shutil
  import numpy
  import tensorflow
  from sklearn import linear_model
  from six.moves import range
  from tcav.cav import CAV, get_or_train_cav
  from tensorflow.python.platform import flags
  from tensorflow.python.platform import googletest
label_desc: Use image node_id 10 for calling the CavTest obj's underlying member method code with example usage: obj.test_train() without return types