code: def make_env(return_reward_idx):
      def thunk():
          env = DummyRewardEnv(return_reward_idx)
          return env
  
      return thunk
  
file_path: gym/tests/wrappers/test_normalize.py
imports: from typing import Optional
  import numpy
  from numpy.testing import assert_almost_equal
  import gym
  from gym.wrappers.normalize import NormalizeObservation, NormalizeReward
label_desc: Use image node_id 1 for calling a global function with example usage: make_env(return_reward_idx) and returns: thunk, env