Python-用Gym创建的脚本在Mac上不起作用

我正在这里学习本教程，以学习深度强化学习（对于这个话题我是很新的）。

当我尝试在Macbook上运行以下脚本时，它会向我返回导入错误（ImportError: sys.meta_path is None, Python is likely shutting down）。我试图从Mac终端以及在Pycharm中运行它，结果相同。我还尝试了其他深度学习脚本，但错误是相同的（似乎与该脚本无关）。

您能帮我理解我哪里错了吗？

脚本：

# Import the gym module
import gym

# Create a breakout environment
env = gym.make('BreakoutDeterministic-v4')
# Reset it, returns the starting frame
frame = env.reset()
# Render
env.render()

is_done = False
while not is_done:
  # Perform a random action, returns the new frame, reward and whether the game is over
  frame, reward, is_done, _ = env.step(env.action_space.sample())
  # Render
  env.render()

错误如下：

/usr/local/bin/python3.6 /Users/marcogdepinto/PycharmProjects/PlayPong/pong.py
2018-05-12 18:58:11.915 Python[567:12594] ApplePersistenceIgnoreState: Existing state will not be touched. New state will be written to (null)
Exception ignored in: <bound method SimpleImageViewer.__del__ of <gym.envs.classic_control.rendering.SimpleImageViewer object at 0x10b65bc88>>
Traceback (most recent call last):
  File "/usr/local/lib/python3.6/site-packages/gym/envs/classic_control/rendering.py", line 347, in __del__
  File "/usr/local/lib/python3.6/site-packages/gym/envs/classic_control/rendering.py", line 343, in close
  File "/usr/local/lib/python3.6/site-packages/pyglet/window/cocoa/__init__.py", line 281, in close
  File "/usr/local/lib/python3.6/site-packages/pyglet/window/__init__.py", line 770, in close
ImportError: sys.meta_path is None, Python is likely shutting down

Process finished with exit code 0