code: def get_protected_settings(self, settings_source):
          
          user_backend = settings_source.get('keyring_backend')
          found_settings = dict()
          for setting_name in self.__PROTECTED_SETTINGS:
              # Nothing to do if the setting is already defined.
              if settings_source.get(setting_name):
                  continue
  
              setting = None
              identifier = "%s.%s" % (self.__name__, setting_name)
              if hasattr(self, 'required') and setting_name in getattr(self, 'required'):
                  setting = self.get_setting_from_keyring(identifier, user_backend)
              elif hasattr(self, setting_name):
                  setting = self.get_setting_from_keyring(identifier, user_backend)
              if setting:
                  found_settings.update({setting_name: setting})
          return found_settings
docs: Attempt to retrieve protected settings from keyring if they are not already set.