Message 336069 - Python tracker

I like the idea. Rejecting float but not decimal.Decimal is inconsistent. __index__ has been written explicitly for this purpose.

I'm always confused and lost in subtle details of the Python and C API in how they handle numbers, so I wrote some notes for myself:
https://pythondev.readthedocs.io/numbers.html

Some functions accept only int, others use __int__, others __index__. Some functions silently truncate into 32 or 64-bit signed integer. Some other raise a OverflowError or ValueError...