public function setISODate($year, $week, $day = null)
    {
        if (self::$_immutable) {
            self::$_immutable = false;
            $newDate = clone $this;
            $newDate->setISODate($year, $week, $day);
            self::$_immutable = true;

            return $newDate;
        } else {
            return parent::setISODate($year, $week, $day);
        }
    }
public function setISODate($year, $week, $day = null)
    {
        if (self::$_immutable) {
            self::$_immutable = false;
            $newDate = clone $this;
            $newDate->setISODate($year, $week, $day);
            self::$_immutable = true;

            return $newDate;
        } else {
            return parent::setISODate($year, $week, $day);
        }
    }
public function setISODate ( $ year , $ week , $ day = null ) { if ( self :: $ _immutable ) { self :: $ _immutable = false ; $ newDate = clone $ this ; $ newDate -> setISODate ( $ year , $ week , $ day ) ; self :: $ _immutable = true ; return $ newDate ; } else { return parent :: setISODate ( $ year , $ week , $ day ) ; } }
Sets the ISO date.

@link http://php.net/manual/en/datetimeimmutable.setisodate.php

@param int      $year
@param int      $week
@param int|null $day

@return DateTimeImmutable
Sets the ISO date .