input: from typing import List
  
  def scrape_headlines(url: str) -> List[str]:
      """ Scrape headlines from a given online news website.
      >>> scrape_headlines("https://www.news.com/")
      ['Headline1', 'Headline2', 'Headline3']
      """
output:     
      import requests
      from bs4 import BeautifulSoup
  
      response = requests.get(url)
      soup = BeautifulSoup(response.content, 'html.parser')
      headlines = [h.text for h in soup.find_all('h2')]
      return headlines
  