TraverseReducible.scala

import cats._
import cats.implicits._

def foo1[A, B: Semigroup, F[_]: Traverse: Reducible, G[_]: Applicative](
  fa: F[A],
  fun: A => G[B]
): G[B] =
  Traverse[F].traverse(fa)(fun).map(Reducible[F].reduce[B])

// foo2 doesn't need F to be Traverse, but needs G to be FlatMap

def foo2[A, B: Semigroup, F[_]: Reducible, G[_]: FlatMap](
  fa: F[A],
  fun: A => G[B]
): G[B] =
  Reducible[F].reduceMapM(fa)(fun)