Treat Option as Monoid if constructed with type that is a Monoid

OptionalMonoid.scala

import scalaz._
import Scalaz._

implicit def OptionMonoid[A : Monoid]: Monoid[Option[A]] = new Monoid[Option[A]] {
  def append(s1: Option[A], s2: => Option[A]) = for (x <- s1; y <- s2) yield implicitly[Monoid[A]].append(x, y)
  val zero = Some(implicitly[Monoid[A]].zero)
}

val optionalNums = (1 to 10) map { some(_) }
optionalNums.asMA.sum.println



optionalNums: scala.collection.immutable.IndexedSeq[Option[Int]] = Vector(Some(1), Some(2), Some(3), Some(4), Some(5), Some(6), Some(7), Some(8), Some(9), Some(10))
Some(55)