input: Write a function to scrape the headlines from an online news website given its URL. The function should use the `requests` library to fetch the HTML content and `BeautifulSoup` from the `bs4` library to parse the content and extract the headlines.
  
  assert scrape_headlines("https://www.news.com/") == []
  assert scrape_headlines("https://www.notanewsurl.com/") == []
  assert scrape_headlines("https://www.example.com/") == []
  assert scrape_headlines("") == []
  assert scrape_headlines("https://www.news.com/") == []
output: def scrape_headlines(url):
      try:
          response = requests.get(url)
          response.raise_for_status()
          soup = BeautifulSoup(response.text, 'html.parser')
          headlines = [h.text for h in soup.find_all('h1')]
          return headlines
      except:
          return []