QtCore.Qt namespace is an unresolved reference on IDEs.

On IDEs like Pycharm, code completion doesn't works for just that specific namespace, and it also throws a warning if we enable Unresolved References warnings from (File / Settings / Editor / Inspections / Python). Those are the 2 main issues that I've found so far. 

  You can reproduce that issue with the next example. 

    from PySide2.QtWidgets import QApplication
    from PySide2.QtCore import Qt

    if _name_ == "_main_": 
         QApplication.setAttribute(Qt.AA_EnableHighDpiScaling)

 If you type QApplication it will complete code without issues, no warnings. If you do the same with Qt then there's no suggestions, and you get a warning.