input: Write a python function to scrape article titles from a given URL using BeautifulSoup and requests.
  assert scrape_titles("http://example.com/articles") == ["Title 1", "Title 2", "Title 3"]
  assert scrape_titles("http://example.com/anotherpage") == ["Another Title 1", "Another Title 2"]
  assert scrape_titles("http://example.com/nopage") == []
output: def scrape_titles(url):
      import requests
      from bs4 import BeautifulSoup
  
      response = requests.get(url)
      if response.status_code != 200:
          return []
  
      soup = BeautifulSoup(response.content, 'html.parser')
      titles = [tag.get_text() for tag in soup.find_all('h1', class_='article-title')]
      return titles