class_docstr: Tests for ValueLearning.
docstr: Tests that loss == 0.5 * td_error^2.
code: def testLoss(self):
      """Tests that loss == 0.5 * td_error^2."""
      with self.test_session() as sess:
          # Loss is 0.5 * td_error^2
          self.assertAllClose(
              sess.run(self.value_learning.loss),
              [2, 2, 2, 2, 1.125, 0.5, 2, 0.5, 0],
          )
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from absl.testing import parameterized
  import tensorflow.compat.v1
  import tree
  from trfl import value_ops
label_desc: Use image node_id 6 for calling the TDLearningTest obj's underlying member method code with example usage: obj.testLoss() without return types