assistance-engine/docs/developer.avapframework.com/chapter9_18.md

6.2.6. Set Displays

A set display is denoted by curly braces and is distinguished from dictionary displays by the absence of colon characters separating keys and values:

set_display ::=  "{" (starred_list | comprehension) "}"

A set display produces a new mutable set object, whose content is specified by a sequence of expressions or a comprehension.