code: func Register(name string, driver kv.Driver) error {
  	name = strings.ToLower(name)
  
  	if _, ok := stores[name]; ok {
  		return errors.Errorf("%s is already registered", name)
  	}
  
  	stores[name] = driver
  	return nil
  }
docs: // Register registers a kv storage with unique name and its associated Driver.