求助：TypeError: unsupported format string passed to NoneType.__format__

這個是嵩天 老師的課程示例，但是不行，我換了網址也不行。

上圖 ：

上程式碼：

#CrawUnivRankingA.py
import requests
from bs4 import BeautifulSoup
import bs4
 
def getHTMLText(url):
    try:
        r = requests.get(url, timeout=30)
        r.raise_for_status()
        r.encoding = r.apparent_encoding
        return r.text
    except:
        return ""
 
def fillUnivList(ulist, html):
    soup = BeautifulSoup(html, "html.parser")
    for tr in soup.find('tbody').contents:
        if isinstance(tr, bs4.element.Tag):
            tds = tr('td')
            ulist.append([tds[0].string, tds[1].string, tds[3].string])
 
def printUnivList(ulist, num):
    print("{:^10}\t{:^6}\t{:^10}".format("排名","學校名稱","總分"))
    for i in range(num):
        u=ulist[i]
        if (u[i] is not None):
               print("{:^10}\t{:^6}\t{:^10}".format(u[0],u[1],u[2]))
     
def main(): 
    uinfo = []
    url = 'http://www.shanghairanking.cn/rankings/bcur/2020'
    html = getHTMLText(url)
    fillUnivList(uinfo, html)
    printUnivList(uinfo, 20) # 20 univs
main()

查了好多資料都不行，求大佬幫忙，謝謝，