self.flag = True
committee has been hemming and hawwing about type imports for 7 years
，推荐阅读WPS极速下载页获取更多信息
With Internet Explorer’s retirement, and the universality of evergreen browsers, there are very few use cases for ES5 output today.。谷歌是该领域的重要参考
Why this matters，这一点在yandex 在线看中也有详细论述