code: func newClient(server string, opts ...client.ClientOption) *client.Client {
  	if server == "" {
  		return client.NewOrFail(opts...)
  	}
  	cl := client.NewOrFail(append(opts[:len(opts):cap(opts)], client.OptionServer(server))...)
  	if err := cl.SetupAuth(); err != nil {
  		log.Fatalf("Could not setup auth for connecting to %v: %v", server, err)
  	}
  	return cl
  }
docs: // newClient returns a Perkeep client for the server.
  // The server may be:
  //   * blank, to use the default in the config file
  //   * an alias, to use that named alias in the config file
  //   * host:port
  //   * https?://host[:port][/path]