Encapsulating Queries in a Custom Django Manager

from django.db import models
from django.utils import timezone

class ArticleQuerySet(models.QuerySet):
    def published(self):
        return self.filter(is_published=True, published_at__lte=timezone.now())

    def by_author(self, user):
        return self.filter(author=user)

class Article(models.Model):
    # ... fields ...
    objects = ArticleQuerySet.as_manager()

# Chainable and readable
recent = Article.objects.published().by_author(request.user)[:5]