from bs4 import BeautifulSoup
import urllib.request

req = urllib.request.Request("http://boards.4chan.org/g/catalog", headers={'User-Agent' : "Magic Browser"})
soup = BeautifulSoup(urllib.request.urlopen(req), "html.parser")
data2 = soup.find_all("div", attrs={"id": "threads"})
print (data2)

data3 = soup.find_all("div", attrs={"class": "thread"})