Resolve several Ruff and Mypy warnings #963

Job	Run time
ruff	7s
mypy	23s
sdist	45s
tox (windows-latest)	2m 10s
tox (ubuntu-latest)	2m 36s
parse_sdl (windows-latest, 2.30.0)	46s
test-docs	1m 31s
parse_sdl (windows-latest, 2.0.14)	47s
parse_sdl (macos-latest, 2.0.14)	21s
parse_sdl (macos-latest, 2.0.16)	25s
build (windows-latest, pypy-3.8, x86)	5m 18s
parse_sdl (windows-latest, 2.0.16)	55s
build (ubuntu-latest, 3.8, x64)	3m 6s
build (windows-latest, 3.8, x86)	4m 43s
linux-wheels (x86_64, cp38-manylinux*)	2m 2s
linux-wheels (x86_64, pp38-manylinux*)	2m 2s
build-macos (cp38-*_universal2)	5m 45s
build (windows-latest, pypy-3.8, x64)	4m 48s
build (ubuntu-latest, pypy-3.8, x64)	3m 2s
parse_sdl (macos-latest, 2.30.0)	21s
linux-wheels (aarch64, pp38-manylinux*)	11m 28s
build-macos (pp38-*)	3m 47s
build (windows-latest, 3.8, x64)	4m 5s
linux-wheels (aarch64, cp38-manylinux*)	12m 22s
publish	-1s
	1h 13m 34s

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