code: def test_max(self):
      self.assertIsInstance(self.qout.max, chainer.Variable)
      np.testing.assert_almost_equal(
          self.qout.max.array, self.q_values.max(axis=1)
      )
  
imports: import unittest
  import chainer
  import chainer.functions
  from chainer import testing
  import numpy
  from chainerrl import action_value
label_desc: Use image node_id 2 for calling the TestDiscreteActionValue obj's underlying member method code with example usage: obj.test_max() without return types