[Pkg-mailman-hackers] Bug#962284: mailman: File "/usr/lib/mailman/cron/cull_bad_shunt", line 77 SyntaxError with Python 3

[Joe Pfeiffer]

Package: mailman
Version: 1:2.1.29-1+deb10u1
Severity: normal

Got the following this morning, after switching to Python 3:

From: root at pfeifferfamily.net (Cron Daemon)
To: list at pfeifferfamily.net
Subject: Cron <list at snowball> [ -x /usr/lib/mailman/cron/cull_bad_shunt ] && /usr/lib/mailman/cron/cull_bad_shunt
Date: Fri, 05 Jun 2020 04:30:01 -0600
Content-Type: text/plain; charset=UTF-8
X-Bogosity: Ham, tests=bogofilter, spamicity=0.000028, version=1.2.4

  File "/usr/lib/mailman/cron/cull_bad_shunt", line 77
    except getopt.error, msg:
                       ^
SyntaxError: invalid syntax

The issue appears to be that Python3 no longer accepts the comma in an
except block.

-- System Information:
Debian Release: bullseye/sid
  APT prefers testing
  APT policy: (700, 'testing'), (650, 'stable'), (600, 'unstable'), (550, 'experimental'), (500, 'oldstable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 5.6.0-1-amd64 (SMP w/8 CPU cores)
Kernel taint flags: TAINT_OOT_MODULE, TAINT_UNSIGNED_MODULE
Locale: LANG=en_US.utf8, LC_CTYPE=en_US.utf8 (charmap=UTF-8), LANGUAGE=en_US.utf8 (charmap=UTF-8)
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages mailman depends on:
ii  apache2 [httpd]        2.4.43-1
ii  cron [cron-daemon]     3.0pl1-136
ii  debconf [debconf-2.0]  1.5.74
ii  libc6                  2.30-4
ii  logrotate              3.16.0-3
ii  lsb-base               11.1.0
ii  python                 2.7.17-2
ii  python-dnspython       1.16.0-1
ii  ucf                    3.0038+nmu1

Versions of packages mailman recommends:
ii  exim4-daemon-light [mail-transport-agent]  4.93-15

Versions of packages mailman suggests:
pn  listadmin      <none>
ii  lynx           2.9.0dev.5-1
pn  mailman3-full  <none>
pn  spamassassin   <none>

-- debconf information excluded