How to add a decorator so that screenshots are taken before and after a function

gistfile1.txt

    def print_jpg(func):
        def inner(*args, **kwargs):
            world.browser.driver.save_screenshot(func.func_name + '.jpg')
            return func(*args, **kwargs)
        return inner


    @print_jpg
    def change_video_speed(speed):
        world.browser.execute_script("$('.speeds').addClass('open')")
        speed_css = 'li[data-speed="{0}"] a'.format(speed)
        world.css_click(speed_css)