AnyIO is an asynchronous networking and concurrency library that works
on top of either asyncio or trio. It implements trio-like structured
concurrency (SC) on top of asyncio, and works in harmony with the
native SC of trio itself.

python3-anyio 3.6.2 is the last possible version for Slackware 15.0.
Newer versions would require a newer python-setuptools and
python-setuptools_scm.