Use the builds from https://github.com/deadsnakes/nightly instead

a repackage of cpython master on 2019-07-17 with the minor version bumped to 3.10

this is available as an ubuntu PPA

sudo add-apt-repository ppa:asottile/python3.10
sudo apt-get update
sudo apt-get install python3.10-dev

there's a significant amount of code which uses sys.version[:3] which will incorrectly report this as version 3.1 -- let's fix this long before it's a problem!

check out flake8-2020 for a flake8 plugin which checks for common related mistakes

python3.10 breaks less code than python4.0

• pypa/virtualenv#1385
• tox-dev/tox#1377
• pypa/setuptools#1824