langchain/document_loaders/youtube.py/YoutubeLoader/extract_video_id
class YoutubeLoader:    def extract_video_id(youtube_url: str) -> str:
        """Extract video id from common YT urls."""
        video_id = _parse_video_id(youtube_url)
        if not video_id:
            raise ValueError(
                f"Could not determine the video ID for the URL {youtube_url}"
            )
        return video_id