编写类 `MyDate` 具有属性年月日，要求一个构造函数初始化属性年月日，提供重置日期、增加日期(考虑闰年闰月)、输出日期等成员函数。

class MyDate:
    def __init__(self, year, month, day):
        self.year = year
        self.month = month
        self.day = day

    def reset_date(self, year, month, day):
        self.year = year
        self.month = month
        self.day = day

    def add_day(self, n):
        days_in_month = [0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]
        if self.is_leap_year():
            days_in_month[2] = 29
        while n > 0:
            days_to_end_of_month = days_in_month[self.month] - self.day + 1
            if n <= days_to_end_of_month:
                self.day += n
                break
            else:
                self.day = 1
                self.month += 1
                if self.month > 12:
                    self.month = 1
                    self.year += 1
                n -= days_to_end_of_month

    def is_leap_year(self):
        if self.year % 400 == 0:
            return True
        elif self.year % 100 == 0:
            return False
        elif self.year % 4 == 0:
            return True
        else:
            return False

    def output_date(self):
        return f"{self.year}-{self.month}-{self.day}"

使用方法：

date = MyDate(2022, 2, 28)
print(date.output_date())  # 2022-2-28

date.add_day(1)
print(date.output_date())  # 2022-3-1

date.reset_date(2021, 12, 31)
print(date.output_date())  # 2021-12-31