我想从我在django中的代码中计算客户购买的总价格

# models.py
from django.db import models

class Order(models.Model):
    product_name = models.CharField(max_length=100)
    unit_price = models.DecimalField(max_digits=10, decimal_places=2)
    quantity = models.IntegerField()

# views.py
from django.shortcuts import render
from .models import Order

def calculate_total_price(request):
    # 接收客户购买商品的请求，保存到数据库中的Order模型中
    if request.method == 'POST':
        product_name = request.POST.get('product_name')
        unit_price = request.POST.get('unit_price')
        quantity = request.POST.get('quantity')
        Order.objects.create(product_name=product_name, unit_price=unit_price, quantity=quantity)

    # 查询数据库获取客户购买的商品列表
    orders = Order.objects.all()

    # 计算总价格
    total_price = 0
    for order in orders:
        total_price += order.unit_price * order.quantity

    return render(request, 'total_price.html', {'total_price': total_price})