code: def test_greedy_actions(self):
      self.assertIsInstance(self.qout.greedy_actions, chainer.Variable)
      np.testing.assert_equal(
          self.qout.greedy_actions.array, self.q_values.argmax(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 4 for calling the TestDistributionalDiscreteActionValue obj's underlying member method code with example usage: obj.test_greedy_actions() without return types