Object of type Modul is not JSON serializable while trying to set the value of another model in the session

Question

i am trying to save the id of a created model in the session so i can update it later in anothe page, but the set function shows me an error

i am using request.session['ORDER'] = serializers.serialize('json', Order.objects.all()) right now but i also used request.session['ORDER'] = order.id, i got the same error

        if form.is_valid():
        if(form.cleaned_data['paymentmethod'] == "PayPal"):
            print("Paypal choosed")
            first_name = form.cleaned_data['first_name']
            last_name = form.cleaned_data['last_name']
            email = form.cleaned_data['email']
            phone = form.cleaned_data['phone']
            address = form.cleaned_data['address']
            zipcode = form.cleaned_data['zipcode']
            place = form.cleaned_data['place']
            paymentmethod = 'pypnt'
            order = checkout(request, first_name, last_name, email, address, zipcode, place, phone,
                             cart.get_total_cost(), paymentmethod)
            print(order.id)
            print(order)
            request.session['ORDER'] = serializers.serialize('json', Order.objects.all())

            return redirect('cart:process')

this is the Order Model

lass Order(models.Model):
first_name = models.CharField(max_length=100)
last_name = models.CharField(max_length=100)
email = models.CharField(max_length=100)
address = models.CharField(max_length=100)
zipcode = models.CharField(max_length=100)
place = models.CharField(max_length=100)
phone = models.CharField(max_length=100)
created_at = models.DateTimeField(auto_now_add=True)
paid_amount = models.DecimalField(max_digits=8, decimal_places=2)
vendors = models.ManyToManyField(Vendor, related_name='orders')
id = models.AutoField(primary_key=True)
class paymentmethod(models.TextChoices):

the error:

Internal Server Error: /de/cart/

raise TypeError(f'Object of type {o.__class__.__name__} '

TypeError: Object of type Product is not JSON serializable