Django and aggregating grand-child records - django

Question

I am new to Django but have been around RdB for a while. I am finally getting the hang of model-view-template. I am struggling a little on "aggregate" and "annotate" especially when my model has grand-child records and I want aggregate.
I use Django 3 on Python 3.
Here is my example setup, I need help straightening it out. I am all sorts of wrong.
There are stores, each that served many pizzas, each pizza has many toppings, each topping used a different qty of items. I want to know the total topping qty for each pizza made and for total topping qty for each store.
models.py
class Parlor(models.Model):
name = models.CharField(max_length=64)
class Pizza(models.Model):
name = models.CharField(max_length=64)
store = models.ForeignKey(Parlor, on_delete=models.CASCADE)
class Topping(models.Model):
name = models.CharField(max_length=64)
pizza = models.ForeignKey(Pizza, on_delete=models.CASCADE)
qty = models.IntegerField(default=0)
views.py
class ParlorDetail(generic.DetailView):
model = Parlor
template_name = 'pizza/parlor_detail.html'
context_object_name = 'parlor'
def get_context_data(self, **kwargs):
context = super(ParlorDetail, self).get_context_data(**kwargs)
id = self.kwargs['pk']
topping_qty = Pizza.objects.filter(parlor=id).annotate(sum=Sum('qty')).aggregate(sum=Sum('qty'))
return context
class PizzaDetail(generic.DetailView):
model = Pizza
template_name = 'pizza/pizza_detail.html'
context_object_name = 'pizza'
def get_context_data(self, **kwargs):
context = super(PizzaDetail, self).get_context_data(**kwargs)
id = self.kwargs['pk']
topping_qty = Topping.objects.filter(pizza=id).annotate(sum=Sum('qty'))
return context
parlor_detail.html
{% extends "pizza/my_base.html" %}
{% block content %}
<div>Parlor: {{ name }}</div>
<div>Pizzas Made at Parlor</div>
{% for pizza in pizzas.all %}
<div>Pizza: {{ pizza.name }}</div>
<div>Toppings: {{ pizza.topping_qty.sum }}</div>
{% endfor %}
<div> Total Qty of Toppings For Parlor: pizzas.topping_qty </div>
{% end block content %}