Scala: 99 Problems/ Problem01: Find the last element of a list in scala

object Scala99Problem01{
  def lastElement[A](ls: List[A]):A  = {
    def lastElementAux[A](ls: List[A]): Option[A] = ls match{
      case Nil      =>  None 
      case x :: Nil =>  Some(x)
      case x :: xs  => lastElementAux (xs) 
    }

    lastElementAux(ls).getOrElse(throw new NoSuchElementException)
  }
}