implicit def diffForLocalDate(difForString: Diff[String]): Diff[LocalDate] =
  new Diff[LocalDate] {
    override def apply(left: LocalDate, right: LocalDate,
                       toIgnore: List[FieldPath]): DiffResult = {
      val formatter = DateTimeFormatter.ISO_DATE
      difForString.apply(formatter.format(left), formatter.format(right))
    }
  }