in core/src/main/scala/com/gu/play/secretrotation/Phase.scala [17:26]
final def accepted: LazyList[T] = LazyList(active) ++ alsoAccepted
def map[S](f: T => S): Phase[S] = {
val activeS = f(active)
val alsoAcceptedS = alsoAccepted.map(f)
new Phase[S] {
val active: S = activeS
val alsoAccepted = alsoAcceptedS
}
}