Add extensions on `DateTime` and `List` #475

Job	Run time
build_local (ubuntu-latest)	1m 45s
build_fetch (ubuntu-latest)	45s
build_checkout (dev, ubuntu-latest)	2m 31s
build_local (macos-latest)	2m 2s
build_fetch (windows-latest)	1m 2s
build_checkout (dev, windows-latest)	5m 40s
build_local (windows-latest)	4m 40s
build_fetch (macos-latest)	57s
build_checkout (dev, macos-latest)	2m 23s
	21m 45s

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