class Bill(models.Model):
    personal_account = models.ForeignKey(Account, blank=True, null=True)
    apartment = models.ForeignKey(Apartment, blank=True, null=True)
    bill_id = models.UUIDField(primary_key=True, default=uuid4, editable=False)
    type_bill = models.CharField(max_length=10)
    brand_name = models.CharField(max_length=10)
    username = models.CharField(max_length=100)
    password = models.CharField(max_length=50)
    is_shared_bill = models.BooleanField()