code: def _init_reward(self):
      for seq_len in range(1, SEQ_LEN + 1):
          for k in itertools.product(CHARACTERS, repeat=seq_len):
              self.reward_map["".join(k)] = 0
      self.reward_map["ABB"] = 5
      self.reward_map["BBB"] = -5
  
imports: import itertools
  import logging
  from collections import deque
  import numpy
  import torch
  from gym import Env
  from gym.spaces import Box, Discrete
label_desc: Use image node_id 2 for calling the StringGameEnv obj's underlying member method code with example usage: obj._init_reward() without return types