code: func (c *Client) HelpRoot() (string, error) {
  	if err := c.condDiscovery(); err != nil {
  		return "", err
  	}
  	if c.helpRoot == "" {
  		return "", ErrNoHelpRoot
  	}
  	return c.helpRoot, nil
  }
docs: // HelpRoot returns the server's help handler.
  // If the server isn't running a help handler, the error will be
  // ErrNoHelpRoot.