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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 post(self, request, *args, **kwargs):
 """ Adds new product to the current shopping cart """

        POST = json.loads(request.body.decode('utf-8'))

        if 'product_pk' in POST and 'quantity' in POST:
            cart = ShoppingCartProxy(request)
            cart.add(
                product_pk=int(POST['product_pk']),
                quantity=int(POST['quantity'])
            )
            return JsonResponse(cart.products)

        return HttpResponseBadRequest()