Import env errors

[mvadrev]

Hello,

I am new to MARL and want to create custom parallel env in PettingZoo and wanted to play with it. I am getting the following import error when attempting to get the environments.

from pettingzoo.butterfly import pistonball_v4 env = pistonball_v4.env()

`
ImportError: cannot import name 'pistonball_v4' from 'pettingzoo.butterfly'
PS C:\Users\mvadr\Desktop\gym>

`

[benblack769]

For me, the code:

from pettingzoo.butterfly import pistonball_v4 
env = pistonball_v4.env()

Work just fine on pettingzoo==1.13.1. Could you say which version of pettingzoo you are running?

[mvadrev]

Hi Thanks for your reply. I am using Colab and installed 1.13.1 with pip but getting the following error.

[benblack769]

I was able to reproduce the problem in colab.

A weird, but effective workaround is to do this:

import pettingzoo.butterfly.pistonball_v4 as pistonball_v4
pistonball_v4.env()

I have no idea why this works and not the earlier statement. Very mysterious. Maybe colab has some special python version they deploy?

[mvadrev]

It is strange indeed but I can confirm I get the same error on my local machine too. Thanks for the fix though!

[benblack769]

Out of curiosity, which python version are you running? I haven't tested it with python 3.9 or 3.10 yet.

[mvadrev]

Hey Ben. its 3.9.9

[benblack769]

Thanks. I'll try to install a python3.9 environment and try to fix this soon.

[nikhilweee]

Can confirm the same. I'm running the 13lines tutorial with pettingzoo 1.12, python 3.8.12, and conda 4.11 on Apple M1.

$ python 13lines.py
Traceback (most recent call last):
  File "13lines.py", line 3, in <module>
    from pettingzoo.butterfly import pistonball_v4
  File "/opt/homebrew/Caskroom/mambaforge/base/envs/rl/lib/python3.8/site-packages/pettingzoo/butterfly/__init__.py", line 5, in __getattr__
    return depricated_handler(env_name, __path__, __name__)
  File "/opt/homebrew/Caskroom/mambaforge/base/envs/rl/lib/python3.8/site-packages/pettingzoo/utils/deprecated_module.py", line 42, in depricated_handler
    raise ImportError(f"cannot import name '{env_name}' from '{module_name}'")
ImportError: cannot import name 'pistonball_v4' from 'pettingzoo.butterfly'

[benblack769]

@nikhilweee If you are using pettingzoo 1.12, this might be expecected behavior---if I'm not mistaken, then that version of pettingzoo contains pistonball_v3, not pistonball_v4.

Try to see if the fix above import pettingzoo.butterfly.pistonball_v4 as pistonball_v4 fixes your issue, and if not if impporting

from pettingzoo.butterfly import pistonball_v3 fixes your issue

[jkterry1]

@benblack769 I just got this bug installing the newest version of pettingzoo on pypi in a virtualenv on GCP too. This is real

[jkterry1]

using pz 1.13.1 and python 3.7.9

[capyun]

hello, i am using python3.8, pettingzoo 1.14.0,
and i get some error:

env = pistonball_v4.parallel_env(n_pistons=20, time_penalty=-0.1,
this raise DeprecatedEnv(f"{name}_v{old_version} is now deprecated, use {name}_v{new_version} instead")
pettingzoo.utils.deprecated_module.DeprecatedEnv: pistonball_v4 is now deprecated, use pistonball_v5 instead

when i use v5
from pettingzoo.butterfly import pistonball_v5
this raise ImportError(f"cannot import name '{env_name}' from '{module_name}'")
ImportError: cannot import name 'pistonball_v5' from 'pettingzoo.butterfly'

[jkterry1]

So, for all future travelers, this issue comes up when upgrading Pettingzoo, for reasons we aren't able to figure out. IF you just uninstall/reinstall, the problem goes away