[transaction] use set operation in the hook control code
We use direct operator on set instead of looping by hand, This simplify the
codes.
# -*- coding: utf-8 -*-# copyright %(year)s %(author)s, all rights reserved.# contact %(author-web-site)s -- mailto:%(author-email)s#%(long-license)s"""%(distname)s views/forms/actions/components for web ui"""