Todo el quilombo que hay que hacer para transformar a JsValue un Map

intento fallido.scala

case class Falopa(valor: Long, mapa: Map[String,Object]) {
}
object Falopa {
  implicit val writes = Json.writes[Falopa]
  implicit val reads = Json.reads[Falopa]
}

  def version() = Action {
    val falopa = new Falopa(1, Map("1" -> new Object()))
    Ok(Json.toJson(falopa))  // falla (el intellj Idea dice: No implicit arguments of type: Writes[Falopa])
 }

Y cuando corrro desde play y lo intento hacer me pasa...

No Json serializer found for type controllers.Falopa. Try to implement an implicit Writes or Format for this type.

In /home/vituchon/development/go_workspace/src/gitlab.com/omniasalud/mvp/app/controllers/Application.scala:281
278  def version = Action {
280    val falopa = new Falopa(1, Map("1" -> new Object()))
281    Ok(Json.toJson(falopa)) 
282  }

Jsoning_A_Map_in.scala

object CookiesStore {
  
  private var sessionDataBySessionId = Map[Long, CookieUserInfo]()

  def asJson(): JsValue = { // taken and adapted from: https://stackoverflow.com/a/27286808/903998
    import play.api.libs.json.Json.JsValueWrapper

    /*implicit val mapReads: Reads[Map[Long, CookieUserInfo]] = new Reads[Map[Long, CookieUserInfo]] {
      def reads(jv: JsValue): JsResult[Map[Long, CookieUserInfo]] =
        JsSuccess(jv.as[Map[Long, CookieUserInfo]].map{case (k, v) =>
          k -> v.asInstanceOf[CookieUserInfo]
        })
    }*/ // Commented due to compilation error ("forward reference extends over definition of value mapReads") and it is not needed to read from json value to Map[Long, CookieUserInfo]

    implicit val mapWrites: Writes[Map[Long, CookieUserInfo]] = new Writes[Map[Long, CookieUserInfo]] {
      def writes(map: Map[Long, CookieUserInfo]): JsValue =
        Json.obj(map.map{case (s, o) =>
          val ret: (String, JsValueWrapper) = s.toString -> Json.toJsFieldJsValueWrapper(o)
          ret
        }.toSeq:_*)
    }

    implicit val mapFormat: Format[Map[Long, CookieUserInfo]] = Format(null, mapWrites)
    Json.toJson(sessionDataBySessionId)
  }

}