code: def delete(cls, label='default', path=None):
          
          if path is None:
              path = _get_config_file_path(
                  cls._xdg_config_dir,
                  cls._xdg_config_file
              )
          cls._file_lock.acquire()
          try:
              with open(path) as config_file:
                  config = json.load(config_file)
              del config[label]
              with open(path, 'w') as config_file:
                  json.dump(config, config_file)
          finally:
              cls._file_lock.release()
docs: Delete a server configuration.
  
          This method is thread safe.
  
          :param label: A string. The configuration identified by ``label`` is
              deleted.
          :param path: A string. The configuration file to be manipulated.
              Defaults to what is returned by
              :func:`nailgun.config._get_config_file_path`.
          :returns: ``None``