如何找到最接近的有效日期作为无效的日期字符串？

from datetime import datetime, timedelta

def parse_date(date_str):
    return datetime.strptime(date_str, '%Y-%m-%d')

def is_valid_date(date):
    try:
        datetime(date.year, date.month, date.day)
        return True
    except ValueError:
        return False

def find_nearest_valid_date(date):
    delta = timedelta(days=1)
    while not is_valid_date(date):
        date += delta
    return date

invalid_date_str = '2022-02-30'
invalid_date = parse_date(invalid_date_str)
nearest_valid_date = find_nearest_valid_date(invalid_date)
nearest_valid_date_str = nearest_valid_date.strftime('%Y-%m-%d')

print(nearest_valid_date_str)