input: 
  def get_all_links(url: str) -> List[str]:
      """ Scrape a given webpage and return a list of all links found on the page.
      >>> get_all_links("http://www.example.com/")
      ['http://www.example2.com/', 'http://www.example3.com/']
      >>> get_all_links("http://www.nonexistentexample.com/")
      []
      """
      import requests as req
      from bs4 import BeautifulSoup
  
      # GET request
      r = req.get(url)
      
      # Parse the downloaded homepage and grab all text
      soup = BeautifulSoup(r.text, "html.parser")
      
      # Find and collect all links
      links = [link.get('href') for link in soup.find_all('a')]
      
      return links
  
output:     # Filter out None values and non-HTTP(S) links
      valid_links = [link for link in links if link and (link.startswith('http://') or link.startswith('https://'))]
      
      return valid_links