code: func StringToSliceHookFunc(sep string) DecodeHookFunc {
  	return func(
  		f reflect.Kind,
  		t reflect.Kind,
  		data interface{}) (interface{}, error) {
  		if f != reflect.String || t != reflect.Slice {
  			return data, nil
  		}
  
  		raw := data.(string)
  		if raw == "" {
  			return []string{}, nil
  		}
  
  		return strings.Split(raw, sep), nil
  	}
  }
docs: // StringToSliceHookFunc returns a DecodeHookFunc that converts
  // string to []string by splitting on the given sep.