python/tornado/websocket 报错 There is no current event loop in thread 'Thread-208'.

报错具体如下：

There is no current event loop in thread 'Thread-208'.

造成原因：

python2升级到python3后，文件夹下有隐藏文件，把文件夹下的“__pycache__”文件夹 和 “.idea” 文件夹 删除

再运行就OK了