input: Write a python function to extract product titles and prices from a webpage. 
  assert extract_titles_and_prices('https://www.example.com') == (['Product 1', 'Product 2'], ['$10', '$20'])
  assert extract_titles_and_prices('https://www.example2.com') == (['Product A', 'Product B'], ['$30', '$40'])
  assert extract_titles_and_prices('https://www.example3.com') == (['Item X', 'Item Y'], ['$50', '$60'])
output: def extract_titles_and_prices(url):
      import requests
      from bs4 import BeautifulSoup
      
      response = requests.get(url)
      soup = BeautifulSoup(response.content, 'html.parser')
      
      titles = [title.get_text() for title in soup.find_all(class_='product-title')]
      prices = [price.get_text() for price in soup.find_all(class_='product-price')]
      
      return (titles, prices)