object SetPackage {
    val (MIN_RANGE, MAX_RANGE) = (-1000, 1000)

    type Set[A] = A => Boolean

    def contains[A](s: Set[A], x: Int): Boolean

    def union[A](s1: Set[A], s2: Set[A]): Set[A]

    def intersection[A](s1: Set[A], s2: Set[A]): Set[A]

    def forall[A](s: Set[A], p: A => Boolean): Boolean

    def exists[A](s: Set[A], p: A => Boolean): Boolean

    def partition[A](s: Set[A], p: A => Boolean): (Set[A], Set[B])

    def take[A](s: Set[A], n: Int): Set[A]

    def takeWhile[A](s: Set[A], p: A => Boolean): Set[A]

    def drop[A](s: Set[A], n: Int): Set[A]

    def dropWhile[A](s: Set[A], p: A => Boolean): Set[A]

    def filter[A](s: Set[A], p: Int => Boolean): Set[A]

    def map[A, B](s: Set[A], f: A => B): Set[B]

    def flatten[A](s: Set[Set[A]]): Set[A]

    def apply[A, B](f: Set[A => B], s: Set[A]): Set[B]

    def bind[A, B](s: Set[A], f: A => Set[B]): Set[B]
}