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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 mark_seen(self, medium):
 """ Creates EventSeen objects for the provided medium for every event in the queryset. Creating these EventSeen objects ensures they will not be returned when passing ``seen=False`` to any of the medium event retrieval functions, ``events``, ``entity_events``, or ``events_targets``. """

        EventSeen.objects.bulk_create([
            EventSeen(event=event, medium=medium) for event in self
        ])