#trzeba zainstalować biblioteki:
# pip install beautifulsoup4
# pip install requests

#python crawler_see_also.py https://en.wikipedia.org/wiki/Online_chat
from bs4 import BeautifulSoup
import requests
import sys

base_wiki_url = "https://en.wikipedia.org{0}"

queue =[]

queue.append(sys.argv[1])
def start():
    for url in queue:
       
        raw_src = requests.get(url).text
        doc = BeautifulSoup(raw_src, 'html.parser')
        try:
            s=doc.select("#See_also")[0].parent.find_next("ul")
        except IndexError:
            continue
        for link in s.find_all('li'):
           
            full_link = base_wiki_url.format(link.a['href'])
            print(full_link)
            queue.append(full_link)

start()