final date = LocalDate(2023, 6, 29);
  print(date);

  final localDateTime = LocalDateTime(2023, 6, 29, 12, 34, 56, 789, 123);
  print(localDateTime.toString());

  final utcDateTime = UtcDateTime(2023, 6, 29, 12, 34, 56, 789, 123);
  print(utcDateTime.toIso8601String());