django - multiple / custom managers

django_managers.py

# managers.py
class ModelClassApprovedOnlyManager(models.Manager):
    def get_query_set():
        self.get_query_set().filter(is_approved=True) 

# models.py
class ModelClass(models.Model):
    # ...
    all_objects = models.Manager()  # first manager used in admin
    objects = ModelClassApprovedOnlyManager()  # second manager used by "objects"

# ------------------------ #

# querysets.py
class EventQuerySet(models.query.QuerySet):
    def published(self):
        return self.filter(is_published=True)

    def upcoming(self):
        return self.filter(start_date__gte=datetime.datetime.now())

# managers.py
class EventManager(models.Manager):
    def get_query_set(self):
        return EventQuerySet(self.model, using=self._db)

    def published(self):
        return self.get_query_set().published()

    def upcoming(self):
        return self.get_query_set().upcoming()

# models.py
class Event(models.Model):
    is_published = models.BooleanField(default=False)
    start_date = models.DateTimeField()
    # ...
    objects = EventManager()    # override the default manager