Como fazer uma busca em Django ignorando acentuação independente de banco de dados

directory_structure.txt

manage.py
utils.py
templates/
 - foo/
    - search.html
foo/
 - models.py
 - views.py

models.py

from django.dispatch import receiver
from django.db import models
from django.db.models.signals import pre_save

from utils import normalize

class Foo(models.Model):
  bar = models.CharField(max_length=255)
  query_string = models.CharField(max_length=255, blank='')

@receiver(pre_save, sender=Foo)
def set_foo_query_string(sender, instance, **kwargs):
    instance.query_string = normalize(instance.bar)

utils.py

import unicodedata

def normalize(value):
  return unicodedata.normalize('NFKD', value).encode('ASCII', 'ignore').decode('utf-8')

views.py

from django.views.generic import ListView

from utils import normalize

from .models import Foo

class SearchView(ListView):
  template_name = 'foo/search.html'
  
  def get_queryset(self):
    params = self.request.GET
    query = params.get('q', '')
    query = normalize(query)
    return Foo.objects.filter(query_string__icontains=query)