Add annotations for returned data #1034

Job	Run time
linters (3.9, ubuntu-latest)	52s
Testing on Python 3.8 (ubuntu-latest)	1m 51s
Testing on Python 3.8 (macos-13)	3m 58s
Testing on Python 3.8 (windows-2019)	2m 43s
Testing on Python 3.9 (ubuntu-latest)	1m 45s
Testing on Python 3.9 (macos-13)	3m 6s
Testing on Python 3.9 (windows-2019)	2m 14s
Testing on Python 3.10 (ubuntu-latest)	1m 39s
Testing on Python 3.10 (macos-13)	3m 4s
Testing on Python 3.10 (windows-2019)	2m 35s
Testing on Python 3.11 (ubuntu-latest)	1m 38s
Testing on Python 3.11 (macos-13)	3m 2s
Testing on Python 3.11 (windows-2019)	3m 39s
Testing on Python 3.12 (ubuntu-latest)	2m 0s
Testing on Python 3.12 (macos-13)	5m 49s
Testing on Python 3.12 (windows-2019)	5m 40s
	45m 35s

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