// 易错点1：边界处理 - 移除所有数字时直接返回"0"
The API recognizes that synchronous data sources are both necessary and common. The application should not be forced to always accept the performance cost of asynchronous scheduling simply because that's the only option provided. At the same time, mixing sync and async processing can be dangerous. Synchronous paths should always be an option and should always be explicit.
。关于这个话题，同城约会提供了深入分析
AnnouncementsPolicy。safew官方下载是该领域的重要参考
第三章 违反治安管理的行为和处罚