code: def test_getitem(self):
      sliced = self.qout[:10]
      np.testing.assert_equal(sliced.q_values.array, self.q_values[:10])
      np.testing.assert_equal(sliced.z_values, self.z_values)
      np.testing.assert_equal(sliced.q_dist.array, self.atom_probs[:10])
      self.assertEqual(sliced.n_actions, self.action_size)
      self.assertIs(
          sliced.q_values_formatter, self.qout.q_values_formatter
      )
  
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 9 for calling the TestDistributionalDiscreteActionValue obj's underlying member method code with example usage: obj.test_getitem() without return types