Why doesn't QSettings save?

Question

Python

What's wrong with the code why it doesn't save but outputs QVariant::save: unable to save type 'QObject*' (type id: 39).

#import subprocess
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtCore import QSize, QCoreApplication, QSettings


from food import Ui_MainWindow      
                                    
ORGANIZATION_NAME = 'Example App'
ORGANIZATION_DOMAIN = 'example.com'
APPLICATION_NAME = 'QSettings program'
SETTINGS_TRAY = 'settings/tray'
class MyWindow(QtWidgets.QMainWindow, Ui_MainWindow):
    def __init__(self, rows):
        super(MyWindow, self).__init__()

        self.rows = rows
        self.setupUi(self)

        self.pushButton.clicked.connect(self.set_row_count)
        self.tableWidget.cellChanged.connect(self.cell_changed)

        self.tableWidget_2.cellChanged.connect(self.cell_changed_2)
        self.pushButton_2.clicked.connect(self.save_table_settings)
        settings = QSettings()

    def save_table_settings(self):
        settings = QSettings()
        settings.setValue(SETTINGS_TRAY, self.tableWidget)
        settings.sync()

    def set_row_count(self):
        self.rows += 1        
        self.tableWidget.setRowCount(self.rows)
        self.tableWidget_2.setRowCount(self.rows)

    def cell_changed(self, row, column):
        _sum = 0
        if column == 2:            
            if self.tableWidget.item(row, column) != None:
                try:
                    _sum +=  int(self.tableWidget.item(row, column).text())
                except:
                    pass

            _bud = 0
            if self.tableWidget.item(row, 1) != None:
                try:
                    _bud = int(self.tableWidget.item(row, 1).text())
                except:
                    pass    
            ost = _bud - _sum            
            self.tableWidget.setItem(row, 3, QtWidgets.QTableWidgetItem(str(ost)))



    def cell_changed_2(self, row, column):
        _sum = 0
        if 0 < column < 6:
            for column in range(1, 5):
                if self.tableWidget_2.item(row, column) != None:
                    try:
                        _sum +=  int(self.tableWidget_2.item(row, column).text())
                    except:
                        pass

            _lgota = 0

            if self.tableWidget_2.item(row, 5) != None :
                try:
                    _lgota = int(self.tableWidget_2.item(row, 5).text())
                except:
                    pass

            ost = _sum - _lgota

            self.tableWidget_2.setItem(row, 6, QtWidgets.QTableWidgetItem(str(ost)))
            self.tableWidget.setItem(row, 2, QtWidgets.QTableWidgetItem(str(ost)))


number_rows = 1


if __name__ == '__main__':
    import sys

    QCoreApplication.setApplicationName(ORGANIZATION_NAME)
    QCoreApplication.setOrganizationDomain(ORGANIZATION_DOMAIN)
    QCoreApplication.setApplicationName(APPLICATION_NAME)

    app = QtWidgets.QApplication(sys.argv)
    w = MyWindow(number_rows)
    w.show()
    sys.exit(app.exec_())

Answer 1

Because you are trying to store a pointer to an object, i.e. just some random number.
You can save what can be converted to QVariant.