code: func DeleteConfigOption(section, key string) error {
  	Cfg.DeleteKey(section, key)
  	if err := goconfig.SaveConfigFile(Cfg, ConfigFile); err != nil {
  		return fmt.Errorf("fail to delete config key(%s:%s): %v", section, key, err)
  	}
  	return nil
  }
docs: // DeleteConfigOption deletes and saves gopm configuration.