input: 
  from typing import List
  
  def extract_links(url: str) -> List[str]:
      """ Scape a webpage and collect all links from it. 
      >>> extract_links("http://www.example.com/")
      ['http://www.iana.org/domains/example']
      """
  
output:     import requests
      from bs4 import BeautifulSoup
  
      response = requests.get(url)
      soup = BeautifulSoup(response.text, 'html.parser')
      links = []
      for link in soup.find_all('a'):
          href = link.get('href')
          if href and href.startswith('http'):
              links.append(href)
      return links