[duskwuff]

Not precisely. {x} is a set literal; {x for y in z} is a set comprehension.

[jdranczewski]

Ah, my bad! I did not know these were a thing, but that makes more sense! Teaches me a thing about only quickly trying things in an online REPL on mobile and jumping to conclusions - I forgot curly braces were also a way to denote a set