[merlincorey]

> ... but to my best knowledge, this behaviour isn't part of the standard.

To the best of my knowledge, Python isn't one such language with a standard, is it?

[ben509]

The standard is documented in PEPs[1]. CPython is the flagship implementation, and many PEPs discuss it directly, but if you're looking to write another Python, that's where you'd go.

https://www.python.org/dev/peps/