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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 _clear_pattern(self):
 """ Clears this event recurrence """

        # pattern group
        self.__interval = None
        self.__days_of_week = set()
        self.__first_day_of_week = None
        self.__day_of_month = None
        self.__month = None
        self.__index = 'first'
        # range group
        self.__start_date = None
        self.__end_date = None
        self.__occurrences = None