DEPR: returning tuple when grouping by a list containing single element
- [X] closes #42795 (Replace xxxx with the Github issue number)
- [X] [Tests added and passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#writing-tests) if fixing a bug or adding a new feature
- [x] All [code checks passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#pre-commit).
- [x] Added an entry in the latest `doc/source/whatsnew/v1.5.0.rst` file if fixing a bug or adding a new feature.
- [x] Applied the removal in #47719

Hello @ahmedibrhm! Thanks for updating this PR. We checked the lines you've touched for [PEP 8](https://www.python.org/dev/peps/pep-0008) issues, and found:















There are currently no PEP 8 issues detected in this Pull Request. Cheers! :beers: 

##### Comment last updated at 2022-08-01 20:13:40 UTC @rhshadrach Thanks a lot for your effort and reviews! How does it look now? @rhshadrach How does it look now? Thanks @ahmedibrhm! Very nice  @ahmedibrhm this is producing a bunch of warnings in the tests.  any chance you can update the relevant tests to avoid/catch these warnings? > @ahmedibrhm this is producing a bunch of warnings in the tests. any chance you can update the relevant tests to avoid/catch these warnings?

I think I caught a lot of them in https://github.com/pandas-dev/pandas/pull/48159 @ahmedibrhm want to make a PR enforcing this deprecation? @jbrockmendel - I'm going to pick this up.