WARN: PerformanceWarning for non-pyarrow fallback
- [x] closes #42613 (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/vX.X.X.rst` file if fixing a bug or adding a new feature.

hmm lots of warnings not being caught
> pandas/tests/strings/test_find_replace.py::test_contains_moar[string[pyarrow]]
  /home/runner/work/pandas/pandas/pandas/tests/strings/test_find_replace.py:182: PerformanceWarning: Falling back on a non-pyarrow code path which may decrease performance. Upgrade to pyarrow >=4 to possibly suppress this warning.
    result = s.str.contains("a") Hello @mroeschke! 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 2022-04-14 01:47:43 UTC