old_contents: from core.models import Service, TenantWithContainer
  
  HELLO_WORLD_KIND = "helloworldservice"
  
  class HelloWorldService(Service):
      KIND = HELLO_WORLD_KIND
  
      class Meta:
  	proxy = True
  	app_label = "helloworldservice"
  	verbose_name = "Hello World Service"
  
  class HelloWorldTenant(TenantWithContainer):
      class Meta:
          proxy = True
  
      KIND = HELLO_WORLD_KIND
      default_attributes = {'display_message': 'Hello World!'}
      def __init__(self, *args, **kwargs):
          helloworld_services = HelloWorldService.get_service_objects().all();
  	if helloworld_services:
              self._meta.get_field("provider_service").default = helloworld_services[0].id
  	
  	self.instance = (helloworld_services[0].slices.all()[0].instances.all()[0])
  	super(HelloWorldTenant, self).__init__(*args, **kwargs)
  
      def save(self, *args, **kwargs):
          super(HelloWorldTenant, self).save(*args, **kwargs)
  
  
      def delete(self, *args, **kwargs):
          self.cleanup_container()
          super(HelloWorldTenant, self).delete(*args, **kwargs)
  
      @property
      def display_message(self):
          return self.get_attribute(
  		"display_message",
  		self.default_attributes['display_message'])
  
      @display_message.setter
      def display_message(self, value):
          self.set_attribute("display_message", value)
  
new_contents: from core.models import Service, TenantWithContainer
  
  HELLO_WORLD_KIND = "helloworldservice"
  
  class HelloWorldService(Service):
      KIND = HELLO_WORLD_KIND
  
      class Meta:
  	proxy = True
  	app_label = "helloworldservice"
  	verbose_name = "Hello World Service"
  
  class HelloWorldTenant(TenantWithContainer):
      class Meta:
          proxy = True
  
      KIND = HELLO_WORLD_KIND
      default_attributes = {'display_message': 'Hello World!'}
      def __init__(self, *args, **kwargs):
          helloworld_services = HelloWorldService.get_service_objects().all();
      	if helloworld_services:
                  self._meta.get_field("provider_service").default = helloworld_services[0].id
      	super(HelloWorldTenant, self).__init__(*args, **kwargs)
  
      def save(self, *args, **kwargs):
          super(HelloWorldTenant, self).save(*args, **kwargs)
  
      def delete(self, *args, **kwargs):
          self.cleanup_container()
          super(HelloWorldTenant, self).delete(*args, **kwargs)
  
      @property
      def display_message(self):
          return self.get_attribute(
  		"display_message",
  		self.default_attributes['display_message'])
  
      @display_message.setter
      def display_message(self, value):
          self.set_attribute("display_message", value)
  
subject: Fix bug