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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 created_by_column(self, obj):
 """ Return user who first created an item in Django admin """

        try:
            first_addition_logentry = admin.models.LogEntry.objects.filter(
                object_id=obj.pk,
                content_type_id=self._get_obj_ct(obj).pk,
                action_flag=admin.models.ADDITION,
            ).get()
            return first_addition_logentry.user
        except admin.models.LogEntry.DoesNotExist:
            return None