Adapter to dump/load JSON format strings and files.
        
        Returns:
            ConfigPersistenceAdapter

def json(self):
        """
        Adapter to dump/load JSON format strings and files.
        
        Returns:
            ConfigPersistenceAdapter
        """
        if self._json_adapter is None:
            self._json_adapter = ConfigPersistenceAdapter(
                config=self,
                reader_writer=JsonReaderWriter(),
            )
        return self._json_adapter