code: def save_config(**kwargs):
      
      if kwargs == {}:
          kwargs = config._config
      current_config = _load_config()
      current_config.update(**kwargs)
      # write to disk
      fname = _get_config_fname()
      if fname is None:
          raise RuntimeError('config filename could not be determined')
      if not op.isdir(op.dirname(fname)):
          os.mkdir(op.dirname(fname))
      with open(fname, 'w') as fid:
          json.dump(current_config, fid, sort_keys=True, indent=0)
docs: Save configuration keys to vispy config file
  
      Parameters
      ----------
      **kwargs : keyword arguments
          Key/value pairs to save to the config file.