Update app.py

app.py

@@ -19,7 +19,7 @@ def process_video(video_file, youtube_url, language_choice):
     if video_file != None and youtube_url != None:
         return None
     elif youtube_url != None:
-        youtube_command = "youtube-dl -o download_video.mp4 " + '"' + youtube_url + '"'
+        youtube_command = f"youtube-dl -o download_video.mp4 \"{youtube_url}\""
         os.system(youtube_command)
         video_file = "download_video.mp4"