title: stable_baselines module error -> 'gym.logger' has no attribute 'MIN_LEVEL'
body: <p>I am trying to use stable_baselines, but any model I try to use gives me the same error:</p>
  <p>module 'gym.logger' has no attribute 'MIN_LEVEL'</p>
  <p>I have attached an example from their website that is giving me the same error. I tried looking online but haven't had any success. Also, I am currently using Conda to create my environment with the following settings.</p>
  <p>Tensorflow: 1.15.0
  Python: 3.7.11</p>
  <p>code bellow.</p>
  <pre><code>import gym
  
  from stable_baselines.common.policies import MlpPolicy
  from stable_baselines.common import make_vec_env
  from stable_baselines import PPO2
  
  # multiprocess environment
  env = make_vec_env('CartPole-v1', n_envs=4)
  
  model = PPO2(MlpPolicy, env, verbose=1)
  model.learn(total_timesteps=25000)
  model.save(&quot;ppo2_cartpole&quot;)
  
  del model # remove to demonstrate saving and loading
  
  model = PPO2.load(&quot;ppo2_cartpole&quot;)
  
  # Enjoy trained agent
  obs = env.reset()
  while True:
      action, _states = model.predict(obs)
      obs, rewards, dones, info = env.step(action)
      env.render()
  </code></pre>
  <p>Full error:</p>
  <pre><code>---------------------------------------------------------------------------
  AttributeError                            Traceback (most recent call last)
  /var/folders/2l/c0wfhk2x0qz3v_6x0ylvvdr00000gn/T/ipykernel_4323/1825670659.py in &lt;module&gt;
        8 env = make_vec_env('CartPole-v1', n_envs=4)
        9 
  ---&gt; 10 model = PPO2(MlpPolicy, env, verbose=1)
       11 model.learn(total_timesteps=25000)
       12 model.save(&quot;ppo2_cartpole&quot;)
  
  ~/miniconda3/envs/tf15/lib/python3.7/site-packages/stable_baselines/ppo2/ppo2.py in __init__(self, policy, env, gamma, n_steps, ent_coef, learning_rate, vf_coef, max_grad_norm, lam, nminibatches, noptepochs, cliprange, cliprange_vf, verbose, tensorboard_log, _init_setup_model, policy_kwargs, full_tensorboard_log, seed, n_cpu_tf_sess)
       95 
       96         if _init_setup_model:
  ---&gt; 97             self.setup_model()
       98 
       99     def _make_runner(self):
  
  ~/miniconda3/envs/tf15/lib/python3.7/site-packages/stable_baselines/ppo2/ppo2.py in setup_model(self)
      108 
      109     def setup_model(self):
  --&gt; 110         with SetVerbosity(self.verbose):
      111 
      112             assert issubclass(self.policy, ActorCriticPolicy), &quot;Error: the input policy for the PPO2 model must be &quot; \
  
  ~/miniconda3/envs/tf15/lib/python3.7/site-packages/stable_baselines/common/base_class.py in __enter__(self)
     1127         self.tf_level = os.environ.get('TF_CPP_MIN_LOG_LEVEL', '0')
     1128         self.log_level = logger.get_level()
  -&gt; 1129         self.gym_level = gym.logger.MIN_LEVEL
     1130 
     1131         if self.verbose &lt;= 1:
  
  AttributeError: module 'gym.logger' has no attribute 'MIN_LEVEL'
  </code></pre>