input: Write a function to extract titles of all YouTube videos from a given URL and return a list of those titles. If there are no titles to extract, return an empty list.
  assert extract_youtube_titles("https://www.youtube.com/user/Thexvid/videos")==['[Title of the first video]','[Title of the second video]','[Title of the third video]']
  assert extract_youtube_titles("https://www.youtube.com/user/NonexistentUser/videos")==[]
  assert extract_youtube_titles("https://www.youtube.com/user/AnotherUser/videos")==['[Title of the video]']
output: def extract_youtube_titles(url):
      import requests
      from bs4 import BeautifulSoup
      
      response = requests.get(url)
      if response.status_code != 200:
          return []
      
      soup = BeautifulSoup(response.text, 'html.parser')
      titles = soup.find_all('a', {'class': 'yt-simple-endpoint style-scope ytd-grid-video-renderer'})
      
      if not titles:
          return []
      
      return [title.get('title') for title in titles]