These look like brackets, not binary operators. So, that's one style, but a rather unobvious one, and also contradicts PEP8, which says (as the very first thing in the section on inline spaces!) to avoid whitespace immediately inside brackets.
So pedantic but I love it. For the GP, what you are looking for is them em dash (—) with no spaces around it, because the dash is its own form of punctuation.
A double-dash is a perfectly valid substitute for an em dash given that most (no?) keyboards have it on a key. Seems like a waste of time to always have to look up an escape code or copy/paste from somewhere when the intent of "--" is clear.
I don't hold random comments on the internet to the highest standard because I am not a monster. However they are not equivalent and the em dash is a sign of extra polish.