def METHOD_NAME(self):
    """Clear any currently displayed data"""
    sceneWidget = self.getSceneWidget()
    items = sceneWidget.getItems()
    if (len(items) == 1 and
            isinstance(items[0], (ScalarField3D, ComplexField3D))):
        items[0].setData(None)
    else:  # Safety net
        sceneWidget.clearItems()