Parsing nullable types with argonaut

FailingExample.scala

import argonaut._
import Argonaut._

object Main extends App{

  val json = "{ \"name\": \"Peter\",  \"score\": null}"
  
  case class Player(name: String, score: String)

  implicit def PlayerCodecJson: CodecJson[Player] =
  casecodec2(Player.apply, Player.unapply)("name", "score")

  println(Parse.decode[Player](json))
}