code: def testInitialize(self):
      agent = categorical_dqn_agent.CategoricalDqnAgent(
          self._time_step_spec,
          self._action_spec,
          self._categorical_net,
          self._optimizer,
      )
  
      observations = tf.constant([[1, 2], [3, 4]], dtype=tf.float32)
      time_steps = ts.restart(observations, batch_size=2)
      actions = tf.constant([0, 1], dtype=tf.int32)
      action_steps = policy_step.PolicyStep(actions)
  
      rewards = tf.constant([10, 20], dtype=tf.float32)
      discounts = tf.constant([0.9, 0.9], dtype=tf.float32)
      next_time_steps = ts.transition(observations, rewards, discounts)
  
      experience = test_utils.stacked_trajectory_from_transition(
          time_steps, action_steps, next_time_steps
      )
  
      loss_info = agent._loss(experience)
      initialize = agent.initialize()
  
      self.evaluate(tf.compat.v1.global_variables_initializer())
      losses = self.evaluate(loss_info).loss
      self.assertGreater(losses, 0.0)
  
      critic_variables = agent._q_network.variables
      target_critic_variables = agent._target_q_network.variables
      self.assertTrue(critic_variables)
      self.assertTrue(target_critic_variables)
      self.evaluate(initialize)
      for s, t in zip(critic_variables, target_critic_variables):
          self.assertAllClose(self.evaluate(s), self.evaluate(t))
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import numpy
  import tensorflow
  from tf_agents.agents.categorical_dqn import categorical_dqn_agent
  from tf_agents.networks import categorical_q_network
  from tf_agents.networks import network
  from tf_agents.networks import q_rnn_network
  from tf_agents.specs import tensor_spec
  from tf_agents.trajectories import policy_step
  from tf_agents.trajectories import test_utils
  from tf_agents.trajectories import time_step
  from tf_agents.trajectories import trajectory
  from tf_agents.utils import common
label_desc: Use image node_id 11 for calling the CategoricalDqnAgentTest obj's underlying member method code with example usage: obj.testInitialize() without return types