How can I validate a `Set` of certain item type?

Hello,

I am trying to create a schema that validates that a property is a set of strings:

const schema = type({
  items: "Set<string>"
});

const schema = type({
  items: "Set<string>"
});

const schema = type({
  items: "Set<string>"
});

const schema = type({
  items: "Set<string>"
});

But that gives me an error.

I checked the docs, and nothing seems to cover Maps or Sets.

Am I missing something, or aren't they supported?

Thanks.