class_docstr: Mock environment for testing.
class_docstr_tok: ["Mock","environment","for","testing","."]
code: def step(self, action):
      self._observation += 1
      action_reward_multiplier = -1 if action > 0 else 1
      reward_multiplier = (
          self.reward_multiplier * action_reward_multiplier
      )
      reward = self._observation * reward_multiplier
      is_terminal = self._observation >= self.max_steps
      self.game_over = is_terminal
  
      unused = 0
      return (self._observation, reward, is_terminal, unused)
  
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.discrete_domains import logger
  import mock
  import numpy
  from tensor2tensor.rl import dopamine_connector
  import tensorflow.compat.v1
label_desc: Use image node_id 3 for calling the MockEnvironment obj's underlying member method code with example usage: obj.step(action) and returns: self,  reward,  is_terminal,  unused