Argonaut decoding alternating JSON type

decode.scala

//In this case, we are decoding a type `Teams` from a third party service
//If `Teams` has any elements, the presented JSON is an Array of `Team`
//If `Teams` is empty, is is suppoed to be Optional.  However, sometimes when `Teams` is empty the service returns an empty JSON object

import argonaut._, Argonaut._

case class Team(id: Int, name: String)

object Team {
 implicit val decodeTeamJson: DecodeJson[Team] = { DecodeJson(h => for {
      id    <- (h --\ "id").as[Int]
      name  <- (h --\ "name").as[String]
    } yield new Team(id, name))
  }
}

type Teams = List[Team]

case class Person(id: Int, name: String, teams: Option[Teams]) 

object Person {
  implicit val decodeJson: DecodeJson[Conference] = { DecodeJson(h => for {
      id    <- (h --\ "id").as[Int]
      name  <- (h --\ "name").as[String]
      teams <- (h --\ "teams").focus match {
        case Some(j) => j.isArray match {
          case true  => j.as[Option[Teams]]
          case false => DecodeResult.ok(None)
        }
        case None    => DecodeResult.ok(None)
      }
    } yield new Conference(id, name, subdivisions, teams))
  }
}