如何抓取li标签下的网址

Question

URL = r'https://data.ipu.org/women-ranking?month=12&year=2019'
Res = requests.get(URL)
soup = BeautifulSoup(Res.text , 'lxml')

ul = soup.find('ul',{'class' : 'exports'})
li = ul.find('li')

for i , link in enumerate(li , start =1):
  try:
      link = item.find("a" )
      link = link.get("href")
  except:
      pass

print(link)
links.append(link)

我收到以下错误消息：'NoneType' object is not iterable

我想抓取所有位于li标记下的href网址