amazing implicits

implicit val intMapFormat = new JsonFormat[Map[Int, Int]] = {
  override def write(map: Map[Int, Int]): JsValue = {
    map.toSeq.toJson
  }
  override def read(json: JsValue): Map[Int, Int] = json match {
    case value: JsArray => value.convertTo[Seq[(Int, Int)]].toMap
    case _: => "Expected . . . "
  } 
} 

val foo =...

implicit val myImplicitFoo = foo