https://mail.python.org/pipermail/mailman-users/2008-August/063035.html
[Mailman-Users] admin_member_chunksize - can't set to larger than 29
https://mail.python.org/pipermail/mailman-users/2004-November/041023.html
[Mailman-Users] DEFAULT_ADMIN_MEMBER_CHUNKSIZE ignored
default adminmailmanusersmemberignored
https://mail.python.org/archives/list/mailman-coders@python.org/message/2RCN2JR6DIDR6VGUHFU5HYQRQQEHXUQJ/
Mailman 3 [ mailman-Bugs-1072002 ] admin_member_chunksize not available in GUI or config_list -...
https://mail.python.org/pipermail/mailman-users/2008-August/063032.html
[Mailman-Users] admin_member_chunksize - can't set to larger than 29