tests

Fix flake8-return warnings #3709

Job	Run time
collateral (diffcov)	5m 34s
test (3.8, ubuntu-latest)	4m 2s
collateral (docs)	1m 1s
test_cygwin (39, windows-latest)	17m 34s
test (3.8, macos-latest)	8m 3s
test (3.8, windows-latest)	9m 53s
test (3.11, ubuntu-latest)	3m 53s
test (3.11, macos-latest)	7m 36s
test (3.11, windows-latest)	10m 9s
test (3.12, ubuntu-latest)	5m 52s
test (3.12, macos-latest)	8m 46s
test (3.12, windows-latest)	10m 27s
test (3.9, ubuntu-latest)	4m 5s
test (3.10, ubuntu-latest)	3m 58s
test (pypy3.10, ubuntu-latest, stdlib)	6m 37s
test (ubuntu-latest, 3.10, stdlib)	3m 55s
integration-test	0s
check	2s
release	0s
	1h 51m 27s

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