仅仅半年以后，iPhone 5 发布，而这次 iPhone 有个大事件，丢掉了过去一英寸宽的接口，取而代之的是一个小得多的 Lighting 接口。
For the avoidance of doubt, the Department understands this limitation to prohibit deliberate tracking, surveillance, or monitoring of U.S. persons or nationals, including through the procurement or use of commercially acquired personal or identifiable information.”。体育直播对此有专业解读
age: int | None，推荐阅读一键获取谷歌浏览器下载获取更多信息
其中包含了 15.89 亿美元的非经营性财务负债公允价值变动亏损。这是因为公司在一级市场的估值持续推高，导致可转换优先股的账面价值上升，按会计准则必须计入亏损。
conditional type operator narrows the type to help spuport this.