def set_mode(self, mode):
        mode = mode.lower()
        if mode == 'tabs':
            self.widget.setViewMode(QtGui.QMdiArea.TabbedView)
        elif mode == 'mdi':
            self.widget.setViewMode(QtGui.QMdiArea.SubWindowView)
        else:
            raise ValueError((mode) % "Don't understand mode='%s'")
dataset/ETHPy150Open ejeschke/ginga/ginga/qtw/Widgets.py/MDIWidget.set_mode/swapped operands of `%`