def get_last(postid):
        '''
        Get the last wiki in history.
        '''
        recs = TabWikiHist.select().where(
            TabWikiHist.wiki_id == postid
        ).order_by(TabWikiHist.time_update.desc())

        return None if recs.count() == 0 else recs.get()
Get the last wiki in history.