code: func (c *Manager) CreateLibraryItemUpdateSession(ctx context.Context, session UpdateSession) (string, error) {
  	url := internal.URL(c, internal.LibraryItemUpdateSession)
  	spec := struct {
  		CreateSpec UpdateSession `json:"create_spec"`
  	}{session}
  	var res string
  	return res, c.Do(ctx, url.Request(http.MethodPost, spec), &res)
  }
docs: // CreateLibraryItemUpdateSession creates a new library item