text: from django.db import models
  from .enum import LEVEL_CHOICES
  
  
  class EntryQuerySet(models.QuerySet):
  
      def published(self):
          return self.filter(publish=True)
  
      def startswith_a(self):
          return self.filter(title__istartswith='a')
  
      def startswith_A(self):
          return self.filter(title__istartswith='A')
  
      def startswith_any_a(self):
          return self.filter(title__startswith='A')
  
      def last_three(self):
          return self.objects.filter(publish=True, since=since).order_by('-created')[:3]
  
  
  class SpeakerQuerySet(models.QuerySet):
      pass
  
  
  class SponsorQuerySet(models.QuerySet):
      pass
  
  
  class EntryManager(models.Manager):
  
      def get_queryset(self):
          return EntryQuerySet(self.model, using=self._db)
  
      def published(self):
          return self.get_queryset().published()
  
      def last_three(self):
          return
  
      def startswith_a(self):
          return self.get_queryset().startswith_a()
  
      def startswith_A(self):
          return self.get_queryset().startswith_A()
  
      def startswith_any_a(self):
          return self.get_queryset().startswith__any_a()
  
  
  class SpeakerManager(models.Manager):
  
      def get_queryset(self):
          return SpeakerQuerySet(self.model, using=self._db)
  
  
  class SponsorManager(models.Manager):
  
      def get_queryset(self):
          return SponsorQuerySet(self.model, using=self._db)
  
      def get_gold(self):
          return self.filter(level='G')
  
      def get_silver(self):
          return self.filter(level='S')
  
      def get_bronze(self):
          return self.filter(level='B')
  
  