PySide6 < 6.1 has no attributes QApplication.exec() and QtWidgets.QMenu.exec()

[kohei-noda-qcrg]

• Users can install PySide6 < 6.1 when using Python < 3.10.

  • PySide6 < 6.1 causes the error described in this issue's title.
  • Using QApplication.exec_() instead of QApplication.exec() fixes the error.

• Error message is following.

  python3.9.exe -m dcaspt2_input_generator
  Traceback (most recent call last):
  File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.9_3.9.3568.0_x64__qbz5n2kfra8p0\lib\runpy.py", line 197, in _run_module_as_main
  return _run_code(code, main_globals, None,
  File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.9_3.9.3568.0_x64__qbz5n2kfra8p0\lib\runpy.py", line 87, in _run_code
  exec(code, run_globals)
  File "C:\Users\none\test\dcaspt2_input_generator\src\dcaspt2_input_generator\__main__.py", line 6, in <module>
  sys.exit(main())
  File "C:\Users\none\test\dcaspt2_input_generator\src\dcaspt2_input_generator\dcaspt2_input_generator.py", line 36, in main
  app.run()
  File "C:\Users\none\test\dcaspt2_input_generator\src\dcaspt2_input_generator\dcaspt2_input_generator.py", line 29, in run
  sys.exit(self.app.exec())
  AttributeError: 'PySide6.QtWidgets.QApplication' object has no attribute 'exec'