input: Write a python function to extract and print the article titles from a Wikipedia page using BeautifulSoup.
  assert extract_article_titles('https://en.wikipedia.org/wiki/Python_(programming_language)') == ["History", "Features and philosophy", "Syntax and semantics", "Programming examples", "Libraries", "Development environments", "Implementations", "History", "Design and philosophy", "References", "Further reading", "External links"]
  assert extract_article_titles('https://en.wikipedia.org/wiki/JavaScript') == ["History", "Trademark", "Features and criticisms", "Syntax", "Semantics", "Standard objects", "Conformance", "Performance", "Security", "Development tools", "Uses", "See also", "Notes", "References", "Further reading", "External links"]
output: def extract_article_titles(url):
      import requests
      from bs4 import BeautifulSoup
  
      response = requests.get(url)
      soup = BeautifulSoup(response.content, 'html.parser')
      
      titles = []
      for header in soup.find_all(['h2', 'h3']):
          title = header.find('span', class_='mw-headline')
          if title:
              titles.append(title.text)
      
      return titles