There are pretty large user bases on centos/rhel 7+8 where python3.6 is the
default version.
If we don't necessarily require any features from 3.7 then it might be worth
lowering this constraint to allow 3.6 or maybe even 3.4 to maximize the
number of users that would benefit.
I realize these python versions are retired according to the python core
team, but I tend to be a little more sympathetic to users when it doesn't
have any impact on the code.
I don't mind 3.6 - I don't need any features from 3.7 or newer.
I draw the line at Python 2, though.