code: def create_agent(self, env):
      model = agents.ddpg.DDPGModel(
          policy=create_deterministic_policy_for_env(env),
          q_func=create_state_action_q_function_for_env(env),
      )
      rbuf = replay_buffer.ReplayBuffer(10**5)
      opt_a = optimizers.Adam()
      opt_a.setup(model.policy)
      opt_b = optimizers.Adam()
      opt_b.setup(model.q_function)
      explorer = explorers.AdditiveGaussian(scale=1)
      return agents.DDPG(
          model, opt_a, opt_b, rbuf, gamma=0.99, explorer=explorer
      )
  
imports: from chainer import optimizers
  from chainer import testing
  import gym
  import gym.spaces
  import basetest_agents
  from chainerrl import agents
  from chainerrl import explorers
  from chainerrl import policies
  from chainerrl import q_functions
  from chainerrl import replay_buffer
  from chainerrl import v_function
label_desc: Use image node_id 1 for calling the TestDDPG obj's underlying member method code with example usage: obj.create_agent(env) and returns: agents