Consider the following set:
s = set(["x", "y", "z"])
How do I create a type hint for a variable that is any subset of the elements in s (short of explicitly creating a Union of every possible subset)?
The closest you can get is annotating the variable as a set whose element type is a literal type:
from typing import Literal
s2: set[Literal['x', 'y', 'z']] = # whatever
Type checkers will recognize that elements of such a set are one of these values, and they will prohibit adding elements that are not one of these values.
Type checkers will not recognize any particular subset relation between such a set and s, and they will not allow passing such a set to a function that takes set[str], as such functions could add other strings to the set.