BSONDocumentReader

  implicit object AccountReader extends BSONDocumentReader[Account] {
    override def read(bson: BSONDocument): Account = {
      val account: Option[Account] = for {
        id <- bson.getAs[BSONObjectID]("_id")
        ...
      } yield new Account(id, ...)
      
      account.getOrElse(boom)
    }
  }