docstr: Helper for normalizing the reward.
docstr_tok: ["Helper","for","normalizing","the","reward","."]
code: def _normalize_reward(
      reward: np.ndarray, env: Optional[VecNormalize] = None
  ) -> np.ndarray:
      """
      Helper for normalizing the reward.
      """
      if env is not None:
          return env.normalize_reward(reward)
      return reward
  
imports: import random
  from typing import Optional, List, Union
  import numpy
  from stable_baselines.common.segment_tree import SumSegmentTree, MinSegmentTree
  from stable_baselines.common.vec_env import VecNormalize
label_desc: Use image node_id 10 for calling the ReplayBuffer obj's underlying member method code with example usage: obj._normalize_reward(reward, env) and returns: reward, env