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## Summary
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First contribution so please let me know if I've made a mistake
anywhere. This was aimed to fix#19982, it adds the isolation level to
PYI021 to in the same style as the PIE790 rule.
fixes: #19982
## Test Plan
<!-- How was it tested? -->
I added a case to the PYI021.pyi file where the two rules are present as
there wasn't a case with them both interacting, using the minimal
reproducible example that @ntBre created on the issue (I think I got the
`# ERROR` markings wrong, so please let me know how to fix that if I
did).
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Co-authored-by: Brent Westbrook <brentrwestbrook@gmail.com>