code: def calc_reward_to_go(reward_list):
      for i in range(len(reward_list) - 2, -1, -1):
          reward_list[i] += reward_list[i + 1]
      return np.array(reward_list)
  
file_path: PARL/benchmark/fluid/QuickStart/train.py
imports: from parl.utils import check_version_for_fluid
  import gym
  import numpy
  import parl
  import os.path
  from cartpole_agent import CartpoleAgent
  from cartpole_model import CartpoleModel
  from parl.utils import logger
label_desc: Use image node_id 2 for calling a global function with example usage: calc_reward_to_go(reward_list) and returns: np