This error happens when using `parse_xml` on any machine that installed yesterday's libexpat update from Debian or Ubuntu.
I opened a bug to Debian: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1006317
Similar issue on Ubuntu: https://bugs.launchpad.net/ubuntu/+source/python-xmltodict/+bug/1961800 (currently misattributed to xmltodict, but xmltodict just happens to use the buggy library)
Right now this isn't an issue in production, but it will be as soon as deposit processes are restarted