Python PyQt6 dataChanged.emit Function

Question

I am trying to run some PyQt6 Model/View Tutorial.

I can't get the dataChange function to work. I tried everything from the web.

model.py

COLS = 3
ROWS = 2

class MyModel(QAbstractTableModel):

    editCompleted = pyqtSignal(str)

    def __init__(self, parent=None):
        super().__init__(parent)
        self._grid_data = [["" for y in range(COLS)] for x in range(ROWS)]
        print(self._grid_data)

    def rowCount(self, parent=None):
        return ROWS

    def columnCount(self, parent=None):
        return COLS

    def data(self, index, role=Qt.ItemDataRole.DisplayRole):
        row = index.row()
        col = index.column()
        print(f"row {row}, col{col}, role {role}")

        if role == Qt.ItemDataRole.DisplayRole:
            if row == 0 and col == 1:
                return "<--left"
            if row == 1 and col == 1:
                return "right-->"
            return f"Row{row}, Column{col+1}"    
        return None
            
    def headerData(self, section, orientation, role=Qt.ItemDataRole.DisplayRole):
   
        if role != Qt.ItemDataRole.DisplayRole:
            return None
        if orientation == Qt.Orientation.Horizontal:
            return f"Column {section}"
        return f"Row {section}"
    def setData(self, index, value, role):
        if role != Qt.ItemDataRole.EditRole or not self.checkIndex(index):
            return False
        self._grid_data[index.row()][index.column()] = value
        result = " ".join(chain(*self._grid_data))
        self.editCompleted.emit(result)
        self.dataChanged.emit(index, index, [Qt.ItemDataRole.EditRole])
        return True
    def flags(self, index):
        return Qt.ItemFlag.ItemIsEditable | super().flags(index)

mainWindow.py

class MainWindow(QMainWindow):
    def __init__(self, parent=None):
        super().__init__(parent)
        self._table_view = QTableView(self)
        self.setCentralWidget(self._table_view)
        myModel = mymodel.MyModel(self)
        self._table_view.setModel(myModel)
        # transfer changes to the model to the window title
        myModel.editCompleted.connect(self.show_window_title)
    @pyqtSlot(str)
    def show_window_title(self, title):
        self.setWindowTitle(title)
if __name__ == "__main__":
    app = QApplication(sys.argv)
    w = MainWindow()
    w.show()
    sys.exit(app.exec())

The title is changing but data inside cell not changing in the end I want to work with Db and it needed to be dynamic.

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