code: def test_params(self):
      self.assertEqual(len(self.qout.params), 1)
      self.assertIs(self.qout.params[0], self.qout.q_dist)
  
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 8 for calling the TestDistributionalDiscreteActionValue obj's underlying member method code with example usage: obj.test_params() without return types