code: func (c *Client) SearchRoot() (string, error) {
  	if err := c.condDiscovery(); err != nil {
  		return "", err
  	}
  	if c.searchRoot == "" {
  		return "", ErrNoSearchRoot
  	}
  	return c.searchRoot, nil
  }
docs: // SearchRoot returns the server's search handler.
  // If the server isn't running an index and search handler, the error
  // will be ErrNoSearchRoot.