in core/src/main/scala/com/gu/play/secretrotation/DualSecretTransition.scala [37:43]
override def decode[T](decodingFunc: String => T, conclusiveDecode: T => Boolean): Option[T] =
Seq(decodingFunc(secret)).find(conclusiveDecode)
override val secrets = new Phase[String] {
val active = secret
val alsoAccepted = Nil
}