bpo-46080: fix argparse help generation exception in edge case (GH-30111)

Fix an uncaught exception during help text generation when
argparse.BooleanOptionalAction is used with default=argparse.SUPPRESS
and help is specified.
(cherry picked from commit 9e87c0e03fa501fb90008547983ce4c1dcaaf90c)

Co-authored-by: Felix Fontein <felix@fontein.de>

Miss Islington (bot) committed 4y ago

e5edc8d737a45d9d8b9b93b8be52f85d79d0f417

Parent: 876ade1

Committed by GitHub <noreply@github.com> on 1/20/2022, 11:13:17 PM