#[\NoDiscard(message: "as DateTimeImmutable::add() does not modify the object itself")]
public function add(DateInterval $interval): DateTimeImmutable

#[\NoDiscard(message: "as DateTimeImmutable::modify() does not modify the object itself")]
public function modify(string $modifier): DateTimeImmutable

#[\NoDiscard(message: "as DateTimeImmutable::setDate() does not modify the object itself")]
public function setDate(int $year, int $month, int $day): DateTimeImmutable

#[\NoDiscard(message: "as DateTimeImmutable::setISODate() does not modify the object itself")]
public function setISODate(int $year, int $week, int $dayOfWeek = 1): DateTimeImmutable

#[\NoDiscard(message: "as DateTimeImmutable::setMicrosecond() does not modify the object itself")]
public function setMicrosecond(int $microsecond): static

#[\NoDiscard(message: "as DateTimeImmutable::setTime() does not modify the object itself")]
public function setTime(
    int $hour,
    int $minute,
    int $second = 0,
    int $microsecond = 0
): DateTimeImmutable

#[\NoDiscard(message: "as DateTimeImmutable::setTimestamp() does not modify the object itself")]
public function setTimestamp(int $timestamp): DateTimeImmutable

#[\NoDiscard(message: "as DateTimeImmutable::setTimezone() does not modify the object itself")]
public function setTimezone(DateTimeZone $timezone): DateTimeImmutable

#[\NoDiscard(message: "as DateTimeImmutable::sub() does not modify the object itself")]
public function sub(DateInterval $interval): DateTimeImmutable

}