Guard access to `code` #850

Job	Run time
test (3.7, ubuntu-latest)	6m 28s
test (3.8, ubuntu-latest)	4m 44s
test (3.9, ubuntu-latest)	4m 49s
test (3.10, ubuntu-latest)	4m 7s
test (3.11, ubuntu-latest)	2m 55s
test (3.12, ubuntu-latest)	4m 16s
test (3.5, ubuntu-20.04)	6s
test (3.6, ubuntu-20.04)	6m 49s
Finish Coveralls processing	0s
	34m 14s

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