code: func (f *FileStore) List() ([]string, error) {
  	keys := make([]string, 0)
  	files, err := f.filesystem.ReadDir(f.directoryPath)
  	if err != nil {
  		return keys, err
  	}
  	for _, f := range files {
  		if !strings.HasPrefix(f.Name(), tmpPrefix) {
  			keys = append(keys, f.Name())
  		}
  	}
  	return keys, nil
  }
docs: // List returns all keys in the store.