Django 5.1
What is the meaning of q.choice_set.all() in the polls app?
https://docs.djangoproject.com/en/5.1/intro/tutorial04/

from django.db.models import F
from django.http import HttpResponse, HttpResponseRedirect
from django.shortcuts import get_object_or_404, render
from django.urls import reverse

from .models import Choice, Question


def vote(request, question_id):
     question = get_object_or_404(Question, pk=question_id)
try:
    selected_choice = question.choice_set.get(pk=request.POST["choice"])
except (KeyError, Choice.DoesNotExist):
    # Redisplay the question voting form.
    return render(
        request,
        "polls/detail.html",
        {
            "question": question,
            "error_message": "You didn't select a choice.",
        },
    )
else:
    selected_choice.votes = F("votes") + 1
    selected_choice.save()
    # Always return an HttpResponseRedirect after successfully dealing
    # with POST data. This prevents data from being posted twice if a
    # user hits the Back button.
    return HttpResponseRedirect(reverse("polls:results", args=(question.id,)))