Update app.py

app.py

@@ -68,7 +68,8 @@ def prepare_media(source_path_or_url: os.PathLike,
     if source_type == 'audio_filepath':
         audio_file = source_path_or_url
     elif source_type == 'youtube_url':
-        os.remove('/download/yt_audio.mp3')
+        if os.path.exists('/download/yt_audio.mp3'):
+            os.remove('/download/yt_audio.mp3')
         # Download from youtube
         with open(log_file, 'w') as lf:
             audio_file = './downloaded/yt_audio'