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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 blob(self, request, pk=None):
 """ fetch large object from pg and gives it back to user via HTTP 1.1 request :param request: django request instance :param pk: requested resource primary key :rtype: django.http.HttpResponse :rtype: HttpResponse :return: file with its filename stored in database """

        obj = self.get_object_or_none()
        if obj:
            blob = obj.get_blob_data()
            content_type = 'octet/stream'
            response = HttpResponse(blob, content_type=content_type,
                                    status=status.HTTP_200_OK)
            response['Content-Disposition'] = (
                'attachment; filename="%s"' % obj.name
            )
            return response
        return HttpResponse('404', status=status.HTTP_404_NOT_FOUND,
                            content_type='application/json')