I installed the compiler package indicated here:
https://wiki.python.org/moin/WindowsCompilers (section titled "Microsoft Visual C++ 14.0 standalone: Build Tools for Visual Studio 2017 (x86, x64, ARM, ARM64)") and get a bunch of this:
d:\programs\python37\include\pystate.h(209): note: see declaration of '_ts'
src/twisted/internet/iocpreactor/iocpsupport/iocpsupport.c(7699): error C2039: 'exc_traceback':
is not a member of '_ts'
d:\programs\python37\include\pystate.h(209): note: see declaration of '_ts'
src/twisted/internet/iocpreactor/iocpsupport/iocpsupport.c(7700): error C2039: 'exc_type': is n
ot a member of '_ts'
d:\programs\python37\include\pystate.h(209): note: see declaration of '_ts'
src/twisted/internet/iocpreactor/iocpsupport/iocpsupport.c(7701): error C2039: 'exc_value': is
not a member of '_ts'
d:\programs\python37\include\pystate.h(209): note: see declaration of '_ts'
src/twisted/internet/iocpreactor/iocpsupport/iocpsupport.c(7702): error C2039: 'exc_traceback':
is not a member of '_ts'
d:\programs\python37\include\pystate.h(209): note: see declaration of '_ts'
error: command 'D:\\Programs\\VS\\VC\\Tools\\MSVC\\14.14.26428\\bin\\HostX86\\x64\\cl.exe' fail
ed with exit status 2
(there was more but this is the gist of it).
Really strongly pointing back at Python 3.7 at this point but it's not where I usually live so ...