• I am on the latest Poetry version.

• I have searched the issues of this repo and believe that this is not a duplicate.

• If an exception occurs when executing a command, I executed it again in debug mode (-vvv option).

• OS version and name: Ubuntu (20.04.2)

• Poetry version: 1.1.5

• Link of a Gist with the contents of your pyproject.toml file: pyproject.toml

Issue

Hello, first of all, thanks for your amazing job!!

I got an error when running poetry on Python 3.10 alpha version.
The reason why I'm using the alpha version in my pipeline is that we want to address possible problems with our library before the official Python release, and we also want to implement some new features in our library using the new features provided by the new version like Pattern Matching! (Disclaimer: We allow failures on Python 3.10 step, so it isn't breaking our pipeline)

You can find the error output below:

Traceback (most recent call last):
  File "/home/runner/.poetry/bin/poetry", line 17, in <module>
    from poetry.console import main
  File "/home/runner/.poetry/lib/poetry/console/__init__.py", line 1, in <module>
    from .application import Application
  File "/home/runner/.poetry/lib/poetry/console/application.py", line 3, in <module>
    from cleo import Application as BaseApplication
ModuleNotFoundError: No module named 'cleo'

For more details, you can also check our pipeline here

I'd like to know if you can provide some help since Python 3.10 wasn't released officially!

Btw, maybe it'll be a great idea to enable Python 3.10 in your pipeline too, you just need to allow failure in that step while the official version isn't released yet! For more information check this out