Tuples in Kotlin ported from Scala

Tuples.kt

data class Tuple1<out T1 : Any>(override val first: T1) : Product1<T1>, Serializable {

  override fun toString(): String {
    return "($first)"
  }
}

data class Tuple2<out T1 : Any, out T2 : Any>(
    override val first: T1,
    override val second: T2) : Product2<T1, T2>, Serializable {

  override fun toString(): String {
    return "($first, $second)"
  }
}

data class Tuple3<out T1 : Any, out T2 : Any, out T3 : Any>(
    override val first: T1,
    override val second: T2,
    override val third: T3) : Product3<T1, T2, T3>, Serializable {

  override fun toString(): String {
    return "($first, $second, $third)"
  }
}

data class Tuple4<out T1 : Any, out T2 : Any, out T3 : Any, out T4 : Any>(
    override val first: T1,
    override val second: T2,
    override val third: T3,
    override val fourth: T4) : Product4<T1, T2, T3, T4>, Serializable {

  override fun toString(): String {
    return "($first, $second, $third, $fourth)"
  }
}