Fontforge-20200314 prevents building my system

Hello, people! I am trying to build my system using the most recent git master, but it complains while trying to build fontforge. Reading the output, it complains about the Python version not being >= 3.

Can someone help me?

Here is a termbin of the installation log.

https://github.com/NixOS/nixpkgs/commit/e9848d11ad038d4077948f14986496ccb14e11bc
updated to fontforge version that no longer supports Python 2:

Monoid expression seems to use python2 environment so it needs to be
ported to Python 3.

How can I set this? I have made no explicit mention to fontforge or python in the expressions.

In the log, you can notice what packages failed to build. fontforge
would likely be pulled in by a font and there is indeed a Monoid font.

Oh, now I understood. I think you was talking about a technical term, not a software…