code: def test_closes_mujoco():
      garage_env = GymEnv("Ant-v2")
      garage_env.visualize()
      assert garage_env._env.viewer is not None
      garage_env.close()
      assert garage_env._env.viewer is None
  
imports: import math
  import pickle
  import gym
  import pytest
  from garage import EnvSpec
  from garage.envs import GymEnv
  from garage.envs.bullet import BulletEnv
  from garage.envs.wrappers.clip_reward import ClipReward
  from garage.envs.wrappers.episodic_life import EpisodicLife
  from garage.envs.wrappers.grayscale import Grayscale
  from garage.envs.wrappers.max_and_skip import MaxAndSkip
  from garage.envs.wrappers.noop import Noop
  from garage.envs.wrappers.resize import Resize
  from garage.envs.wrappers.stack_frames import StackFrames
label_desc: Use image node_id 3 for calling a global function with example usage: test_closes_mujoco() without return types