old_contents: 
  from django.apps import apps, AppConfig
  from django.utils.translation import ugettext_lazy as _
  
  
  default_app_config = 'site_config.SiteConfigApp'
  
  __all__ = ['default_app_config', 'SiteConfig']
  
  
  class SiteConfigApp(AppConfig):
      name = 'site_config'
      verbose_name = _("Settings")
  
  
  class SiteConfig(object):
  
      def __getattr__(self, name):
  
          if name.startswith('_'):
              return super(SiteConfig, self).__getattribute__(name)
  
          if not hasattr(self, '_cached_fields'):
              self._cached_fields = self.get_fields()
  
          if name in self._cached_fields:
              return self._cached_fields[name].value
  
          return None
  
      def get_fields(self):
          fields = apps.get_model('site_config', 'ConfigField').objects.all()
          return {f.name: f for f in fields}
  
      def reload(self):
          if hasattr(self, '_cached_fields'):
              del self._cached_fields
  
  
  config = SiteConfig()
  
new_contents: 
  from django.apps import apps, AppConfig
  from django.utils.translation import ugettext_lazy as _
  
  
  default_app_config = 'site_config.SiteConfigApp'
  
  
  class SiteConfigApp(AppConfig):
      name = 'site_config'
      verbose_name = _("Settings")
  
  
  class SiteConfig(object):
  
      def __getattr__(self, name):
  
          if name.startswith('_'):
              return super(SiteConfig, self).__getattribute__(name)
  
          if not hasattr(self, '_cached_fields'):
              self._cached_fields = self.get_fields()
  
          if name in self._cached_fields:
              return self._cached_fields[name].value
  
          return None
  
      def get_fields(self):
          fields = apps.get_model('site_config', 'ConfigField').objects.all()
          return {f.name: f for f in fields}
  
      def reload(self):
          if hasattr(self, '_cached_fields'):
              del self._cached_fields
  
  
  config = SiteConfig()
  
subject: Remove __all__.