PyCharm引入自定义类报错

This inspection detects names that should resolve but don't. Due to dynamic dispatch and duck typing, this is possible in a limited but useful number of cases. Top-level and class-level items are supported better than instance items.

上面大致意思：

import 不能识别自定义包名，该类或者包没有灌入python引入库中

解决方案：右击pycharm中项目名-->Mark Directory as -->Resource root

意思：自定义的资源加入到该项目中，这样才能被 import 识别