code: func (c *Config) SaveRestClient(client *tags.RestClient) error {
  	if !c.Persist {
  		return nil
  	}
  
  	p, err := c.restSessionFile()
  	if err != nil {
  		return err
  	}
  
  	log.Printf("[DEBUG] Will persist REST client session data to %q", p)
  	err = os.MkdirAll(filepath.Dir(p), 0700)
  	if err != nil {
  		return err
  	}
  
  	err = ioutil.WriteFile(p, []byte(client.SessionID()), 0600)
  	if err != nil {
  		return err
  	}
  
  	return nil
  }
docs: // SaveRestClient saves the REST client session ID to the supplied path. This
  // facilitates re-use of the session at a later date.