planetstack/core/models/singletonmodel.py

from django.db import models

class SingletonModel(models.Model):
    class Meta:
        abstract = True
 
    def save(self, *args, **kwargs):
        self.__class__.objects.exclude(id=self.id).delete()
        super(SingletonModel, self).save(*args, **kwargs)
 
    @classmethod
    def load(cls):
        try:
            return cls.objects.get()
        except cls.DoesNotExist:
            return cls()