fun haveFun(person: Person<Parent>) {
  //Everyone can have fun!
}

// Usage:
fun main(args: Array<String>) {
  // This will work. It's an supertype of `Parent`.
  haveFun(Person<GrandParent>())

  // This will work. It's an exact type.
  haveFun(Person<Parent>())

  // This will work. It's a subtype of `Parent`
  haveFun(Person<BabyChild>())
}