code: func (c *Manager) ListLibraryItems(ctx context.Context, id string) ([]string, error) {
  	url := internal.URL(c, internal.LibraryItemPath).WithParameter("library_id", id)
  	var res []string
  	return res, c.Do(ctx, url.Request(http.MethodGet), &res)
  }
docs: // ListLibraryItems returns a list of all items in a content library.