SemigroupHKT.scala

object SuppliedSemigroup {
  import cats.kernel.Semigroup

  implicit val maxDurationSemigroup: Semigroup[Duration] = Semigroup((a, b) => if (a > b) a else b)
  // implicit val optionMonoid: Monoid[Option[Duration]] = cats.kernel.instances.option.catsKernelStdMonoidForOption(maxDurationSemigroup)
  
  def optionDurationCombineSemigroup(rp1: Option[Duration], rp2: Option[Duration])(implicit mo: Semigroup[Option[Duration]]): Option[Duration] = {
    mo.combine(rp1, rp2)
  }

  def main(args: Array[String]): Unit = {
    println(optionDurationCombineSemigroup(Some(2.minute), Some(90.seconds)))
  }
}