tests

Fix type errors #131

Job	Run time
Tests (8.1, ubuntu-latest, prefer-lowest)	1m 24s
Tests (8.1, ubuntu-latest, prefer-stable)	1m 24s
Tests (8.1, macos-latest, prefer-lowest)	1m 51s
Tests (8.1, macos-latest, prefer-stable)	2m 51s
Tests (8.1, windows-latest, prefer-lowest)	1m 32s
Tests (8.1, windows-latest, prefer-stable)	1m 39s
Tests (8.2, ubuntu-latest, prefer-lowest)	1m 22s
Tests (8.2, ubuntu-latest, prefer-stable)	1m 16s
Tests (8.2, macos-latest, prefer-lowest)	2m 2s
Tests (8.2, macos-latest, prefer-stable)	1m 47s
Tests (8.2, windows-latest, prefer-lowest)	1m 55s
Tests (8.2, windows-latest, prefer-stable)	1m 35s
Tests (8.3, ubuntu-latest, prefer-lowest)	1m 27s
Tests (8.3, ubuntu-latest, prefer-stable)	1m 14s
Tests (8.3, macos-latest, prefer-lowest)	2m 43s
Tests (8.3, macos-latest, prefer-stable)	1m 51s
Tests (8.3, windows-latest, prefer-lowest)	1m 34s
Tests (8.3, windows-latest, prefer-stable)	2m 0s
	31m 27s

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