langchain/document_loaders/youtube.py/GoogleApiYoutubeLoader/_get_document_for_video_id
class GoogleApiYoutubeLoader:    def _get_document_for_video_id(self, video_id: str, **kwargs: Any) -> Document:
        captions = self._get_transcripe_for_video_id(video_id)
        video_response = (
            self.youtube_client.videos()
            .list(
                part="id,snippet",
                id=video_id,
            )
            .execute()
        )
        return Document(
            page_content=captions,
            metadata=video_response.get("items")[0],
        )