Django: Two questions on extending ListView with get_context_data - django

Question

I tried something similar to this. I have three models:
class PartBase(models.Model):
name = models.CharField('Name', max_length=120)
price = models.DecimalField("Price per part", decimal_places=2, max_digits=6)
class Sett(models.Model):
name = models.CharField('Name', max_length=120)
class PartRelation(models.Model):
part = models.ForeignKey(PartBase, on_delete=models.CASCADE)
qty = models.PositiveIntegerField("Quantity")
sett = models.ForeignKey(Sett, related_name='setts', on_delete=models.SET_NULL, null=True)
def get_position_price(self):
return self.qty * self.part.price
now I want to add the price of all the items in a Sett in a row in my HTML.
{% extends 'base.html' %}
{% block title %}
Add Set
{% endblock title %}
{% block content %}
<table class="table">
<tr>
<th>Set Name</th>
<th>Total price</th>
</tr>
{% for set in setts %}
<tr>
<td>{{ set.name }}</td>
<td>{{ set.test }}</td>
</tr>
{% endfor %}
</table>
{% endblock %}
I wanted to override the get_context_data method somehow like this:
class SetListView(ListView):
model = Sett
context_object_name = "setts"
def get_context_data(self,**kwargs):
context = super(SetListView, self).get_context_data(**kwargs)
context['test'] = "price"
return context
But I only get an empty field in the template (which I assumed would have the word "price".
I can access the price in the shell via
for s in Sett.objects.all():
pr = PartRelation.objects.filter(sett=s)
price = 0
for p in pr:
price += p.get_position_price()
But how would I put the code from the shell in the get_context_data() function, so that for every row I get the corresponding total price?

Answer 1

This did the trick:
class SetListView(ListView):
model = Sett
context_object_name = "setts"
def get_context_data(self, **kwargs):
context = super(SetListView, self).get_context_data(**kwargs)
for s in context["setts"]:
pr = PartRelation.objects.filter(sett=s)
s.total_price = 0
for p in pr:
s.total_price += p.get_position_price()
return context
I would gladly get feedback if that is a good approach (and why not/how to do better).