Allows you to turn List[Either[A,B]] in to a Tuple2[List[A],List[B]]

PimpedListOfEither.scala

  implicit class PimpedListOfEither[A,B](list: List[Either[A,B]]) {
    def tupled = {
      @tailrec
      def traverseList(curList: List[Either[A,B]], transformedList: (List[A], List[B]) = (List.empty[A], List.empty[B])): (List[A], List[B]) = {
        traverseList(
          curList.tail,
          curList.headOption map {
            case Left(a) => (a :: transformedList._1, transformedList._2)
            case Right(b) => (transformedList._1, b :: transformedList._2)
          } getOrElse transformedList)
      }
      traverseList(list)
    }
  }