以下是我目前的代码，应该怎么修改：
import re
from bs4 import BeautifulSoup
import requests
from lxml import etree

flink = re.compile(r'<a class="img" href="(.*?)"')

headers={'User-Agent':'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/92.0.4515.159 Safari/537.36'}
r=requests.get(f'http://tipdm.com/',headers=headers)

print(r)

s=BeautifulSoup(r.text,'html.parser')

print(s)

a=s.find_all('div',{'class':"bd"})

print(a)

for item in a:
item=str(item)
link = re.findall(flink, item)
print(link)

这样试试

for item in a:
    item=str(item)
    link = re.findall(flink, item)
    if len(link)>0:    
        print(link)