input: Write a python function to extract video titles from a YouTube channel page.
  assert extract_video_titles("https://www.youtube.com/user/Thexvid/videos") != []
  assert all(isinstance(title, str) for title in extract_video_titles("https://www.youtube.com/user/Thexvid/videos"))
  assert len(extract_video_titles("https://www.youtube.com/user/Thexvid/videos")) > 0
output: import requests
  from bs4 import BeautifulSoup
  
  def extract_video_titles(channel_url):
      response = requests.get(channel_url)
      soup = BeautifulSoup(response.content, 'html.parser')
      titles = []
      for title in soup.find_all('a', attrs={'title': True}):
          titles.append(title['title'])
      return titles