[_library.py] implement array_jit decorator correctly

Fixes #64
8 jobs for issue-64 in 11 minutes and 15 seconds (queued for 7 seconds)
Status Job ID Name Coverage
  Build
passed #238051
docker
build_linux_37

00:09:23

80.0%
passed #238052
docker
build_linux_38

00:09:39

81.0%
passed #238049
intel macos
build_macos_intel_37

00:11:15

80.0%
passed #238050
intel macos
build_macos_intel_38

00:11:13

81.0%
failed #237965
docker
build_linux_37

00:21:11

failed #237966
docker
build_linux_38

00:21:14

failed #237963
intel macos
build_macos_intel_37

00:18:25

failed #237964
intel macos
build_macos_intel_38

00:18:41