fix crash with keyword decorator on class libraries #1188

Job	Run time
static_checks (3.8, ubuntu-latest)	49s
test (3.8, ubuntu-latest, 6.1.1, 8.0)	2m 10s
static_checks (3.8, macos-latest)	3m 20s
test (3.8, ubuntu-latest, 6.1.1, from lockfile)	1m 59s
static_checks (3.8, windows-latest)	1m 16s
test (3.8, ubuntu-latest, from lockfile, 8.0)	2m 6s
static_checks (3.12, ubuntu-latest)	47s
test (3.8, ubuntu-latest, from lockfile, from lockfile)	1m 53s
static_checks (3.12, macos-latest)	26s
test (3.8, macos-12, 6.1.1, 8.0)	2m 26s
static_checks (3.12, windows-latest)	1m 26s
test (3.8, macos-12, 6.1.1, from lockfile)	2m 3s
test (3.8, macos-12, from lockfile, 8.0)	2m 4s
test (3.8, macos-12, from lockfile, from lockfile)	2m 59s
test (3.8, windows-latest, 6.1.1, 8.0)	2m 58s
test (3.8, windows-latest, 6.1.1, from lockfile)	2m 40s
test (3.8, windows-latest, from lockfile, 8.0)	3m 2s
test (3.8, windows-latest, from lockfile, from lockfile)	2m 33s
test (3.12, ubuntu-latest, 6.1.1, 8.0)	2m 13s
test (3.12, ubuntu-latest, 6.1.1, from lockfile)	2m 2s
test (3.12, ubuntu-latest, from lockfile, 8.0)	2m 9s
test (3.12, ubuntu-latest, from lockfile, from lockfile)	1m 57s
test (3.12, macos-12, 6.1.1, 8.0)	3m 11s
test (3.12, macos-12, 6.1.1, from lockfile)	2m 11s
test (3.12, macos-12, from lockfile, 8.0)	2m 6s
test (3.12, macos-12, from lockfile, from lockfile)	1m 53s
test (3.12, windows-latest, 6.1.1, 8.0)	3m 18s
test (3.12, windows-latest, 6.1.1, from lockfile)	2m 47s
test (3.12, windows-latest, from lockfile, 8.0)	3m 3s
test (3.12, windows-latest, from lockfile, from lockfile)	2m 44s
publish	0s
	1h 6m 31s

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