python 递归计算若干工作日后的日期

import datetime

　　
# 根据第一次计算出来的休息日数，计算还需要的工作日数。（递归调用）
    def get_next_date(self, start_date, weekend_days):
        if not weekend_days:
            return start_date
        new_weekend_days = 0
        next_date = datetime.datetime.strptime(start_date.strftime("%Y-%m-%d"), "%Y-%m-%d")
        for day in range(1, weekend_days + 1):
            next_date = datetime.datetime.strptime(start_date.strftime("%Y-%m-%d"), "%Y-%m-%d") + datetime.timedelta(days=day)
            if next_date.weekday() in (5, 6):
                new_weekend_days += 1
        if new_weekend_days:
            next_date = self.get_next_date(next_date, new_weekend_days)
        return next_date

    def workdays(self, receiv_date, testing_cycle=0, warning_days=0):
        weekend_days = 0
        days = testing_cycle - warning_days
        if not days or not receiv_date:
            return ""
        next_date = datetime.datetime.strptime(receiv_date, "%Y-%m-%d")
        # 首次计算包含周六、周日的天数
        for day in range(1, days+1):
            next_date = datetime.datetime.strptime(receiv_date, "%Y-%m-%d") + datetime.timedelta(days=day)
            if next_date.weekday() in (5, 6):
                weekend_days += 1
        end_date = weekend_days and self.get_next_date(next_date, weekend_days) or next_date
        return end_date.strftime("%Y-%m-%d")