text: """
  Task is to reverse content over the input tape.
  http://arxiv.org/abs/1511.07275
  """
  
  import numpy as np
  from gym.envs.algorithmic import algorithmic_env
  from gym.envs.algorithmic.algorithmic_env import ha
  
  class ReverseEnv(algorithmic_env.AlgorithmicEnv):
      def __init__(self, base=2):
          algorithmic_env.AlgorithmicEnv.__init__(self,
                                                  inp_dim=1,
                                                  base=base,
                                                  chars=True)
          algorithmic_env.AlgorithmicEnv.current_length = 1
          self.last = 50
  
      def set_data(self):
          self.content = {}
          self.target = {}
          for i in range(self.total_len):
              val = self.np_random.randint(self.base)
              self.content[ha(np.array([i]))] = val
              self.target[self.total_len - i - 1] = val
          self.total_reward = self.total_len + 0.9
  