Update app.py

app.py

@@ -142,7 +142,7 @@ async def get_transcript(youtube_url: str):
         cookiefile = "firefox-cookies.txt"
         ydl_opts["cookiefile"] = cookiefile
 
-        with YoutubeDL(ydl_opts) as ydl:
+        with yt_dlp.YoutubeDL(ydl_opts) as ydl:
             info = ydl.extract_info(youtube_url, download=False)
             subtitles = info.get('subtitles', {})
             auto_subtitles = info.get('automatic_captions', {})