How to generate a list of n unique elements picked from a collection?

How can I use ScalaCheck to generate a list of n unique values ​​( Gen[List[T]]) from a set of values ​​(not a generator) ? This post is not using Gen[T]*a set of values ​​and I can't seem to override it to make it work.

edit

At @Jubobs' request, I now shamelessly show what I've tried so far, showing my newbie status when using ScalaCheck :-)

I just tried replacing the duplicate gs: Gen[T]parameters with the solution Set@Eric wrote here :

def permute[T](n: Int, gs: Set[T]): Gen[Seq[T]] = {
    val perm = Random.shuffle(gs.toList)
    for {
        is <- Gen.pick(n, 1 until gs.size)
        xs <- Gen.sequence[List[T], T](is.toList.map(perm(_)))
    } yield xs
}

But is.toList.map(perm(_))with a red underline, IntelliJ IDEA tells me "You should read the ScalaCheck API first before blind (albeit intuitive) trial and error" , or maybe "Type mismatch, should be expected: Traversable[Gen[T]], Actual List[T]" , I don't remember.

I've also tried several other approaches, most of which are absurd in hindsight (and thus not worth posting), the most naive of which is to use @Eric's (otherwise useful and neat) solution as-is:

val g = for (i1 <- Gen.choose(0, myList1.length - 1); 
  i2 <- Gen.choose(0, myList2.length - 1)) 
  yield new MyObject(myList1(i1), myList2(i2))
val pleaseNoDuplicatesPlease = permute(4, g, g, g, g, g)

After some testing I found that pleaseNoDuplicatesPleaseactually contains duplicates, at which point I weighed having to read the ScalaCheck API and have more knowledge than I do now (inevitably and gradually), or post my question on StackOverflow (after searching carefully for similar issues).