input: Write a python function to extract blog post titles from a given URL.
  assert extract_blog_titles("https://example.com/blog") == ["Post Title 1", "Post Title 2", "Post Title 3"]
  assert extract_blog_titles("https://example.com/another-blog") == ["Another Post Title 1", "Another Post Title 2"]
output: def extract_blog_titles(url):
      import requests
      from bs4 import BeautifulSoup
  
      response = requests.get(url)
      soup = BeautifulSoup(response.content, 'html.parser')
      
      titles = []
      for title in soup.find_all('h2', class_='post-title'):
          titles.append(title.get_text())
      
      return titles