def save(self, filename=None):
        filename = Path(filename) if filename is not None else self.filename
        with filename.open("w") as f:
            f.write(self.yaml)
def on_lower_bound_changed(self):
        self.ui.spinBoxUpperBound.setMinimum(self.ui.spinBoxLowerBound.value())
        self.ui.spinBoxBoundaryNumber.setMaximum(math.ceil((self.ui.spinBoxUpperBound.value()
                                                            - self.ui.spinBoxLowerBound.value()) / 2))