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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 _init_date_range(self, start_date=None, end_date=None):
 """Set date range defaults if no dates are passed"""

        self.end_date = end_date
        self.start_date = start_date
        if self.end_date is None:
            today = now_utc().date()
            end_date = self.event.end_dt.date()
            self.end_date = end_date if end_date < today else today
        if self.start_date is None:
            self.start_date = self.end_date - timedelta(days=ReportBase.default_report_interval)