如何使用django框架和sqlite验证优惠券？

django-admin startproject myproject
cd myproject
django-admin startapp coupons

from django.db import models

class Coupon(models.Model):
    code = models.CharField(max_length=50, unique=True)
    discount = models.DecimalField(max_digits=5, decimal_places=2)
    valid_from = models.DateTimeField()
    valid_to = models.DateTimeField()
    active = models.BooleanField(default=True)

    def __str__(self):
        return self.code

python manage.py makemigrations
python manage.py migrate

from django.http import JsonResponse
from django.views.decorators.http import require_http_methods
from .models import Coupon
from django.utils import timezone

@require_http_methods(["POST"])
def validate_coupon(request):
    data = request.POST
    code = data.get('code')
    try:
        coupon = Coupon.objects.get(code=code, active=True, valid_from__lte=timezone.now(), valid_to__gte=timezone.now())
        return JsonResponse({'valid': True, 'discount': str(coupon.discount)})
    except Coupon.DoesNotExist:
        return JsonResponse({'valid': False})

from django.urls import path
from .views import validate_coupon

urlpatterns = [
    path('validate/', validate_coupon, name='validate_coupon'),
]

from django.contrib import admin
from django.urls import path, include

urlpatterns = [
    path('admin/', admin.site.urls),
    path('coupons/', include('coupons.urls')),
]