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.
并不影响程序的正常运行，但pycharm有下波浪线
在pycharm中设置source路径
file–>setting（或者ctrl+alt+s）–>project structure
将放package的文件夹设置为source，这样import的模块类等，就是通过这些source文件夹作为根路径来查找，也就是在这些source文件夹中查找import的东西。