tests

Fix flake8-return warnings #3706

Job	Run time
test_cygwin (39, windows-latest)	4m 43s
test (3.8, ubuntu-latest)	2m 51s
collateral (diffcov)	4m 3s
test (3.8, macos-latest)	3m 6s
collateral (docs)	1m 0s
test (3.8, windows-latest)	2m 53s
test (3.11, ubuntu-latest)	2m 49s
test (3.11, macos-latest)	3m 9s
test (3.11, windows-latest)	2m 54s
test (3.12, ubuntu-latest)	3m 7s
test (3.12, macos-latest)	3m 8s
test (3.12, windows-latest)	2m 56s
test (3.9, ubuntu-latest)	2m 55s
test (3.10, ubuntu-latest)	3m 8s
test (pypy3.10, ubuntu-latest, stdlib)	3m 7s
test (ubuntu-latest, 3.10, stdlib)	3m 5s
integration-test	0s
check	3s
release	1s
	48m 58s

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