Add typing in api.py #409

Job	Run time
Test on python 3.7 and ubuntu-latest	2m 1s
Test on python 3.7 and windows-latest	1m 58s
Test on python 3.7 and macos-latest	19s
Test on python 3.8 and ubuntu-latest	1m 48s
Test on python 3.8 and windows-latest	1m 51s
Test on python 3.8 and macos-latest	49s
Test on python 3.9 and ubuntu-latest	1m 42s
Test on python 3.9 and windows-latest	1m 54s
Test on python 3.9 and macos-latest	24s
Test on python 3.10 and ubuntu-latest	1m 50s
Test on python 3.10 and windows-latest	1m 54s
Test on python 3.10 and macos-latest	27s
Test on python 3.11 and ubuntu-latest	1m 27s
Test on python 3.11 and windows-latest	1m 51s
Test on python 3.11 and macos-latest	38s
Test on python 3.12 and ubuntu-latest	1m 37s
Test on python 3.12 and windows-latest	1m 50s
Test on python 3.12 and macos-latest	56s
	25m 16s

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