src/YearMonth.php
public function atDay(int $day) : LocalDate
    {
        return LocalDate::of($this->year, $this->month, $day);
    }
public function atDay(int $day) : LocalDate
    {
        return LocalDate::of($this->year, $this->month, $day);
    }
public function atDay ( int $ day ) : LocalDate { return LocalDate :: of ( $ this -> year , $ this -> month , $ day ) ; }
Combines this year-month with a day-of-month to create a LocalDate.

@param int $day The day-of-month to use, valid for the year-month.

@return LocalDate The date formed from this year-month and the specified day.

@throws DateTimeException If the day is not valid for this year-month.
Combines this year - month with a day - of - month to create a LocalDate .