input: Write a function to create a web scraper in Python that can extract hotel reviews from TripAdvisor. The function should take an URL as input, request the HTML from that URL, parse it, and extract review titles and text. If the review has a title and text, print them, otherwise skip the review. If there are no reviews found, print a message indicating so. The function should also include a user agent in the request headers to mimic a browser request.
  
  assert tripadvisor_scraper('<url>')==None
  assert tripadvisor_scraper('<url_with_reviews>')
  # Expected to print review titles and texts
  assert tripadvisor_scraper('<url_invalid>')
  # Expected to print "No reviews found"
output: import requests
  from bs4 import BeautifulSoup
  
  def tripadvisor_scraper(url):
      headers = {'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.3'}
      response = requests.get(url, headers=headers)
      soup = BeautifulSoup(response.text, 'html.parser')
      
      reviews = soup.find_all('div', class_='review-container')
      
      if not reviews:
          print("No reviews found")
          return
      
      for review in reviews:
          title = review.find('span', class_='noQuotes')
          text = review.find('p', class_='partial_entry')
          
          if title and text:
              print(f"Title: {title.text.strip()}")
              print(f"Text: {text.text.strip()}")
              print()