def enableEditing(self, enabled):
        """Enable the editing buttons to add/remove rows/columns and to edit the data.

        This method is also a slot.
        In addition, the data of model will be made editable,
        if the `enabled` parameter is true.

        Args:
            enabled (bool): This flag indicates, if the buttons
                shall be activated.

        """
        for button in self.buttons[1:]:
            button.setEnabled(enabled)
            if button.isChecked():
                button.setChecked(False)

        model = self.tableView.model()

        if model is not None:
            model.enableEditing(enabled)