old_contents: from __future__ import print_function
  from __future__ import unicode_literals
  from __future__ import division
  from __future__ import absolute_import
  from builtins import *  # NOQA
  from future import standard_library
  standard_library.install_aliases()  # NOQA
  
  import gym
  
  
  class ScaleReward(gym.RewardWrapper):
      """Scale reward by a scale factor.
  
      Args:
          env: Env to wrap.
          scale (float): Scale factor.
  
      Attributes:
          original_reward: Reward before casting.
      """
  
      def __init__(self, env, scale):
          super().__init__(env)
          self.scale = scale
  
      def _reward(self, reward):
          self.original_reward = reward
          return self.scale * reward
  
new_contents: from __future__ import print_function
  from __future__ import unicode_literals
  from __future__ import division
  from __future__ import absolute_import
  from builtins import *  # NOQA
  from future import standard_library
  standard_library.install_aliases()  # NOQA
  
  import gym
  
  
  class ScaleReward(gym.RewardWrapper):
      """Scale reward by a scale factor.
  
      Args:
          env: Env to wrap.
          scale (float): Scale factor.
  
      Attributes:
          scale: Scale factor.
          original_reward: Reward before casting.
      """
  
      def __init__(self, env, scale):
          super().__init__(env)
          self.scale = scale
  
      def _reward(self, reward):
          self.original_reward = reward
          return self.scale * reward
  
subject: Document scale attribute