OpenAI gym mujoco ImportError: No module named ‘mujoco_py.mjlib‘

题意：OpenAI Gym Mujoco 导入错误：没有名为 'mujoco_py.mjlib' 的模块

问题背景：

I try to run this code in openAi gym. but it can not.

我尝试在 OpenAI Gym 中运行这段代码，但无法运行

import mujoco_py
import gym
from os.path import dirname

env = gym.make('Hopper-v1')
env.reset()
for _ in range(1000):
    env.render()
    env.step(env.action_space.sample()) 

the error info:        错误信息：

/Users/yunfanlu/anaconda/envs/py35/bin/python3.5 /Users/yunfanlu/WorkPlace/OpenAIGym/OpenGymL/c.py
[2017-07-23 17:17:15,633] Making new env: Hopper-v1
Traceback (most recent call last):
  File "/Users/yunfanlu/anaconda/envs/py35/li