fix AI:Decisiontree (#248) #700

Job	Run time
get_dependencies	4m 8s
base_build (-bullseye, arm/v7)	4m 10s
base_build (-bullseye, amd64)	49s
base_build (-bullseye, arm64)	4m 12s
base_build (-bullseye, 386)	55s
base_build (-threaded-bullseye, arm/v7)	4m 8s
base_build (-threaded-bullseye, amd64)	45s
base_build (-threaded-bullseye, arm64)	4m 0s
base_build (-threaded-bullseye, 386)	1m 1s
test_build (-bullseye)	17m 46s
test_build (-threaded-bullseye)	16m 6s
cpan_build (-bullseye, arm/v7)	1h 8m 47s
cpan_build (-bullseye, arm64)	1h 10m 43s
cpan_build (-bullseye, 386)	6m 4s
cpan_build (-threaded-bullseye, arm/v7)	1h 9m 33s
cpan_build (-threaded-bullseye, arm64)	1h 12m 42s
cpan_build (-threaded-bullseye, 386)	6m 25s
published_build (-bullseye)	11m 20s
published_build (-threaded-bullseye)	11m 13s
	6h 14m 47s

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