in anghammarad/src/main/scala/com/gu/anghammarad/Enrichments.scala [8:15]
def traverseT[B](f: A => Try[B]): Try[List[B]] = {
as.foldRight[Try[List[B]]](Success(Nil)) { (a, acc) =>
for {
b <- f(a)
bs <- acc
} yield b :: bs
}
}