OpenAI gym with Grayscling Wrapper return ValueError: too many values to unpack (expected 2)

Got issue with the gym package since I imported GrayScaleObservation from gym.wrappers.
I know where the issue is located as it is mentioned in the logs but I don't know how the fix it ...

Here the imports:

# Import Frame Stacker Wrapper and Grayscling Wrapper
from gym.wrappers import FrameStack, GrayScaleObservation

Here is the Error:

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
/Users/adhuy/code/led8/AI tools/Nicholas Renotte/Reinforcement Learning/mario_tutotial.ipynb Cell 19 in 5
      2 env = JoypadSpace(env, SIMPLE_MOVEMENT)
      3 env = GrayScaleObservation(env, keep_dim=True) 
----> 5 env.reset()

File ~/.pyenv/versions/3.10.6/envs/lewagon/lib/python3.10/site-packages/gym/core.py:379, in ObservationWrapper.reset(self, **kwargs)
    377 def reset(self, **kwargs):
    378     """Resets the environment, returning a modified observation using :meth:`self.observation`."""
--> 379     obs, info = self.env.reset(**kwargs)
    380     return self.observation(obs), info

ValueError: too many values to unpack (expected 2)

Normally the code below should return (240, 256, 1), the shape of the array. Actually when I ran this code without GrayScaleObservation(env, keep_dim=True) , everything works well.

Here is my code and what I try to meet:

env = gym_super_mario_bros.make('SuperMarioBros-v0')
env = JoypadSpace(env, SIMPLE_MOVEMENT)
env = GrayScaleObservation(env, keep_dim=True) 

state = env.reset()
state.shape

Working through a similar project myself right now and encountered the same error.

Even though I cannot give more insight to why exactly things are causing errors (hopefully someone else will eventually enlighten us) I can give you the fix that seems to have worked for me and produces the expected results:

Replace the lines causing errors within core.py with:

def reset(self, **kwargs):
        obs = self.env.reset(**kwargs)
        return self.observation(obs)

Deleting info might cause similar errors in following wrappers in case you´re using more. I also used DummyVecEnv for further processing, leading me to replace the reset method within dummy_vec_env.py aswell:

def reset(self) -> VecEnvObs:
        for env_idx in range(self.num_envs):
            obs = self.envs[env_idx].reset(seed=self._seeds[env_idx])
            self._save_obs(env_idx, obs)
        # Seeds are only used once
        self._reset_seeds()
        return self._obs_from_buf()

...replacing this original line:

obs, self.reset_infos[env_idx] = self.envs[env_idx].reset(seed=self._seeds[env_idx])

Going from error to error fixing them in similar ways should do the trick. I´m unsure weather removing the info provided might cause problems in other projects, but for getting gym_super_mario_bros to run it seems to work.