'Updates the current color theme, depending on the value of :attr:`theme_name`.'

def update_theme(self):

    if (self.theme_name.lower() == 'default'):
        self.set_palette(OWPalette.System)
    elif (self.theme_name.lower() == 'light'):
        self.set_palette(OWPalette.Light)
    elif (self.theme_name.lower() == 'dark'):
        self.set_palette(OWPalette.Dark)
