code: def test_scale_reward(self):
      env = chainerrl.wrappers.ScaleReward(
          gym.make(self.env_id), scale=self.scale
      )
      self.assertIsNone(env.original_reward)
      self.assertAlmostEqual(env.scale, self.scale)
  
      _ = env.reset()
      _, r, _, _ = env.step(env.action_space.sample())
  
      if self.env_id == "CartPole-v1":
          # Original reward must be 1
          self.assertAlmostEqual(env.original_reward, 1)
          self.assertAlmostEqual(r, self.scale)
      elif self.env_id == "MountainCar-v0":
          # Original reward must be -1
          self.assertAlmostEqual(env.original_reward, -1)
          self.assertAlmostEqual(r, -self.scale)
      else:
          assert False
  
imports: import unittest
  from chainer import testing
  import gym
  import chainerrl
label_desc: Use image node_id 1 for calling the TestScaleReward obj's underlying member method code with example usage: obj.test_scale_reward() without return types