code: def test_runningmeanstd():
      """Test RunningMeanStd object"""
      for x_1, x_2, x_3 in [
          (np.random.randn(3), np.random.randn(4), np.random.randn(5)),
          (
              np.random.randn(3, 2),
              np.random.randn(4, 2),
              np.random.randn(5, 2),
          ),
      ]:
          rms = RunningMeanStd(epsilon=0.0, shape=x_1.shape[1:])
  
          x_cat = np.concatenate([x_1, x_2, x_3], axis=0)
          moments_1 = [x_cat.mean(axis=0), x_cat.var(axis=0)]
          rms.update(x_1)
          rms.update(x_2)
          rms.update(x_3)
          moments_2 = [rms.mean, rms.var]
  
          assert np.allclose(moments_1, moments_2)
  
file_path: stable-baselines/tests/test_vec_normalize.py
imports: import subprocess
  import gym
  import numpy
  import pytest
  from stable_baselines import DDPG, DQN, SAC, TD3
  from stable_baselines.common.running_mean_std import RunningMeanStd
  from stable_baselines.common.vec_env import DummyVecEnv, VecNormalize, VecFrameStack, sync_envs_normalization, unwrap_vec_normalize
  from .test_common import _assert_eq
label_desc: Use image node_id 2 for calling a global function with example usage: test_runningmeanstd() without return types