tests

mypy: fix all assignment #1471

Job	Run time
test_msvc_python_mingw	3m 22s
ci_setuptools (3.10, ubuntu-latest)	3m 15s
test_msys2_mingw (clang64, clang-x86_64, clang, clang++)	1m 58s
test_msys2_mingw (mingw64, x86_64, gcc, g++)	1m 38s
test_msys2_mingw (mingw32, i686, gcc, g++)	1m 41s
collateral (diffcov)	51s
collateral (docs)	30s
test_cygwin (39, windows-latest)	6m 20s
test (3.9, macos-latest)	8m 44s
test (3.9, ubuntu-latest)	52s
test (3.11, ubuntu-latest)	52s
test (3.10, ubuntu-latest)	54s
test (3.13, ubuntu-latest)	52s
test (3.13, macos-latest)	51s
test (3.13, windows-latest)	2m 11s
test_msys2_mingw (ucrt64, ucrt-x86_64, gcc, g++)	1m 37s
test (3.14, ubuntu-latest)	1m 29s
test (pypy3.10, ubuntu-latest)	4m 20s
test (3.9, windows-latest)	2m 20s
test (3.12, ubuntu-latest)	1m 4s
check	4s
release	0s
	45m 45s

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