input: Write a python function to get the top ten trending YouTube video titles. 
  assert len(get_trending_videos()) == 10
  assert isinstance(get_trending_videos(), list)
output: def get_trending_videos():
      import requests
      
      API_KEY = 'YOUR_YOUTUBE_API_KEY'
      TRENDING_URL = f'https://www.googleapis.com/youtube/v3/videos?part=snippet&chart=mostPopular&regionCode=US&maxResults=10&key={API_KEY}'
      
      response = requests.get(TRENDING_URL)
      
      if response.status_code != 200:
          return []
      
      videos = response.json().get('items', [])
      
      trending_titles = [video['snippet']['title'] for video in videos]
      
      return trending_titles