code: func GetLastDay(year, month int) int {
  	var day = 0
  	if month > 0 && month <= 12 {
  		day = daysByMonth[month-1]
  	}
  	if month == 2 && isLeapYear(uint16(year)) {
  		day = 29
  	}
  	return day
  }
docs: // GetLastDay returns the last day of the month