Mailman

has been hopelessly hacked into oblivion with the addition of recaptcha. https://ftp.libre-soc.org/recaptcha-mashed-into-oblivion.tgz

this was itself out-of-date due to python-recaptcha itself being out-of-date

https://www.dragonsreach.it/2014/05/03/adding-recaptcha-support-to-mailman/

also remember to add this:

 ln -s /usr/lib/python2.7/dist-packages/recaptcha \
       /usr/lib/python2.7/site-packages/recaptcha

don't ask.