代码中没有出现“key”，出现“key”报错，怎么解决

求解下面错误解决办法：
Traceback (most recent call last):
File "E:\python\untitled\test_photo.py", line 18, in
img_url = img['stc']
File "E:\python\python\lib\site-packages\bs4\element.py", line 1406, in getitem
return self.attrs[key]
KeyError: 'stc'

r = requests.get(url=url,headers=headers)
print(r)  #返回200表示成功发送请求
r.encoding = "utf-8"
page_text = r.text
soup = BeautifulSoup(r.content,'lxml')
#print(soup)
all_img = soup.select("div.list ul a img")
#print(all_img.text)
for img in all_img:
    img_url = img['stc']
    print(img_url)
    root = r'E:\python\untitled\ji'   #图片存储根目录
    path = root + img_url.split('/')[0]   #重命名
    try:
        if not os.path.exists(root):
            os.mkdir(root)
            if not os.path.exists(path):
                print(url)
                r = requests.get(img_url)
                print(r)
                with open(path,'wb')as f:
                    f.write(r.content)
                    f.close()
                    print("文件保存成功！")
            else:
                print("文件已存在！")
        else:
            print("爬取失败！！！")
    except:
        print("error")

是src, 不是stc, 你写错了

img中没有取到 stc 所以报错

你输出一下img 看看是什么值