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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 find(self, instance_ids=None, filters=None):
 """Flatten list of reservations to a list of instances. :param instance_ids: A list of instance ids to filter by :type instance_ids: list :param filters: A dict of Filter.N values defined in http://goo.gl/jYNej9 :type filters: dict :return: A flattened list of filtered instances. :rtype: list """

        instances = []
        reservations = self.retry_on_ec2_error(self.ec2.get_all_instances, instance_ids=instance_ids, filters=filters)
        for reservation in reservations:
            instances.extend(reservation.instances)
        return instances