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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 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()