Definitions.scala

object LivesIn {
  def unapply(p: Person): Option[Seq[String]] =
    Some(
      for(r <- p.residence)
      yield r.city
    )
}

class StringSeqContains(value: String) {
  def unapply(in: Seq[String]): Boolean =
    in contains value
}

val Istanbul = new StringSeqContains("Istanbul")