tests

Fix flake8-return warnings #3707

Job	Run time
test_cygwin (39, windows-latest)	12m 28s
test (3.8, ubuntu-latest)	4m 6s
collateral (diffcov)	4m 9s
test (3.8, macos-latest)	3m 15s
collateral (docs)	59s
test (3.8, windows-latest)	2m 55s
test (3.11, ubuntu-latest)	2m 56s
test (3.11, macos-latest)	3m 14s
test (3.11, windows-latest)	3m 3s
test (3.12, ubuntu-latest)	3m 13s
test (3.12, macos-latest)	3m 20s
test (3.12, windows-latest)	3m 7s
test (3.9, ubuntu-latest)	2m 58s
test (3.10, ubuntu-latest)	3m 13s
test (pypy3.10, ubuntu-latest, stdlib)	3m 13s
test (ubuntu-latest, 3.10, stdlib)	3m 14s
integration-test	0s
check	4s
release	0s
	59m 27s

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