def METHOD_NAME(self):
    if self._app.config.THEME == 'auto':
        if sys.platform == 'darwin':
            if get_osx_theme() == 1:
                theme = DARK
            else:
                theme = LIGHT
        else:
            theme = self.guess_system_theme()
            if theme == DARK:
                theme = Dark
    else:  # user settings have highest priority
        theme = self._app.config.THEME
    self.load_theme(theme)