code: function advisoryLock(callback) {
        if (!(req.htmlPageId && req.user)) {
          // Some consumers of this API might not participate
          // in advisory locking. Also, make sure we have a
          // valid user to minimize the risk of a DOS attack
          // via nuisance locking
          return callback(null);
        }
        return self.apos.docs.lock(req, docId, req.htmlPageId, callback);
      }
docs: Grab an advisory lock, letting other users and tabs know who is editing this right now