seleniumchrome更改文件下载路径无效

#设置浏览器

chrome_optiOns= webdriver.ChromeOptions()

# chrome_options.add_argument("--headless")

chrome_options.add_argument('log-level=3')  

prefs = {"download.default_directory": 'F:\a\python\selenium',

"profile.managed_default_content_settings.images":2,

"download.prompt_for_download": False}

chrome_options.add_experimental_option("prefs",prefs)

driver = webdriver.Chrome(chrome_optiOns=chrome_options)