Set the range of recurrence

        :param date start: Start date of repetition
        :param date end: End date of repetition
        :param int occurrences: no of occurrences

def set_range(self, start=None, end=None, occurrences=None):
        """ Set the range of recurrence

        :param date start: Start date of repetition
        :param date end: End date of repetition
        :param int occurrences: no of occurrences
        """
        if start is None:
            if self.__start_date is None:
                self.__start_date = dt.date.today()
        else:
            self.start_date = start

        if end:
            self.end_date = end
        elif occurrences:
            self.__occurrences = occurrences
        self._track_changes()