code: def _agent_step(self, reward, observation):
      # We verify that rewards are clipped (and set by MockEnvironment as a
      # function of observation)
      expected_reward = 1 if observation % 2 else -1
      self.assertEqual(expected_reward, reward)
      return observation % 2
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import os
  import shutil
  from absl import flags
  from dopamine.agents.dqn import dqn_agent
  from dopamine.agents.implicit_quantile import implicit_quantile_agent
  from dopamine.agents.rainbow import rainbow_agent
  from dopamine.discrete_domains import checkpointer
  from dopamine.discrete_domains import logger
  from dopamine.discrete_domains import run_experiment
  from dopamine.metrics import collector_dispatcher
  from dopamine.metrics import statistics_instance
  import gin.tf
  import mock
  import tensorflow
label_desc: Use image node_id 1 for calling the RunnerTest obj's underlying member method code with example usage: obj._agent_step(reward, observation) and returns: unknown