def prep_for_audit(self):
        """
        Prepare for the audit by calculating 90 days ago.
        This is used to check if access keys have been rotated.
        """
        now = datetime.datetime.now()
        then = now - datetime.timedelta(days=90)
        self.ninety_days_ago = then.replace(tzinfo=tz.gettz('UTC'))
dataset/ETHPy150Open Netflix/security_monkey/security_monkey/auditors/iam/iam_user.py/IAMUserAuditor.prep_for_audit/original