input: def build_web_scraper(url: str) -> List[str]:
      """ Build a web scraper in Python that collects all the links from a given website.
      The function should return a list of all URLs found on the page.
      >>> build_web_scraper("http://www.example.com/")
      ['http://www.example.com/link1', 'http://www.example.com/link2', 'http://www.example.com/link3']
      """
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