input: Write a python function to extract all href links from a given URL and return them as a list.
  assert extract_links("http://example.com") == ['http://www.iana.org/domains/example']
  assert extract_links("http://test.com") == ['http://test.com/link1', 'http://test.com/link2']
  assert extract_links("http://anotherexample.com") == ['http://anotherexample.com/home', 'http://anotherexample.com/about']
output: import requests
  from bs4 import BeautifulSoup
  
  def extract_links(url):
      response = requests.get(url)
      soup = BeautifulSoup(response.content, 'html.parser')
      links = [a['href'] for a in soup.find_all('a', href=True)]
      return links