Install this version:
emerge -a =dev-perl/Schedule-At-1.150.0# Copyright 1999-2021 Gentoo Authors
# Distributed under the terms of the GNU General Public License v2
EAPI=8
DIST_AUTHOR=JOSERODR
DIST_VERSION=1.15
inherit perl-module
DESCRIPTION="OS independent interface to the Unix 'at' command"
SLOT="0"
KEYWORDS="amd64 x86"
RDEPEND="
sys-process/at
"
BDEPEND="${RDEPEND}"