PySide6 WidgetsQComboBox.NoInsert (or whatever policy) should likely be QComboBox.InsertPolicy.NoInsert
super(MainWindow, self).__init__() could be super().__init__() throughout...as of Python3.0 super was changed to drop explicit naming of parent class source reference
PySide6 Layoutsfor n, color in enumerate(["red", "green", "blue", "yellow"]): could be for color in ["red", "green", "blue", "yellow"]
in menus lesson label.setAlignment(Qt.AlignCenter) should likely be label.setAlignment(Qt.AlignmentFlag.AlignCenter)
QComboBox.NoInsert(or whatever policy) should likely beQComboBox.InsertPolicy.NoInsertsuper(MainWindow, self).__init__()could besuper().__init__()throughout...as of Python3.0 super was changed to drop explicit naming of parent class source referencefor n, color in enumerate(["red", "green", "blue", "yellow"]):could befor color in ["red", "green", "blue", "yellow"]label.setAlignment(Qt.AlignCenter)should likely belabel.setAlignment(Qt.AlignmentFlag.AlignCenter)