Set to repeat every week on specified days for every x no. of days

        :param int interval: no. of days to repeat at
        :param str first_day_of_week: starting day for a week
        :param list[str] days_of_week: list of days of the week to repeat
        :keyword date start: Start date of repetition (kwargs)
        :keyword date end: End date of repetition (kwargs)
        :keyword int occurrences: no of occurrences (kwargs)

def set_weekly(self, interval, *, days_of_week, first_day_of_week,
                   **kwargs):
        """ Set to repeat every week on specified days for every x no. of days

        :param int interval: no. of days to repeat at
        :param str first_day_of_week: starting day for a week
        :param list[str] days_of_week: list of days of the week to repeat
        :keyword date start: Start date of repetition (kwargs)
        :keyword date end: End date of repetition (kwargs)
        :keyword int occurrences: no of occurrences (kwargs)
        """
        self.set_daily(interval, **kwargs)
        self.__days_of_week = set(days_of_week)
        self.__first_day_of_week = first_day_of_week