Comment 3 for bug 1922504

Fwiw, the issue got fixed in Debian and I tried to get it included in the Ubuntu 21.04 release, but I suppose it was too close to release for that (bug 1924907). In any case, it should soon be synced to the new development release, Impish.

If you would like a fix for older Ubuntu releases such as 20.04, I can try to help out with a Stable Release Update (https://wiki.ubuntu.com/StableReleaseUpdates#Procedure). Although as mentioned above, a manual install of python3-future will also resolve the issue :)