in pan-domain-auth-verification/src/main/scala/com/gu/pandomainauth/service/CryptoConf.scala [144:148]
private def conciseList[T](s: Seq[T]): String = s.mkString("[", ",", "]")
case class SeqDiff[T](added: Seq[T], removed: Seq[T]) {
val summary: String = s"added ${conciseList(added)}, removed ${conciseList(removed)}"
}