UPDATE

app.py

@@ -184,7 +184,7 @@ async def audio_effect_handler(event):
 
     query = event.pattern_match.group(1).decode("UTF-8")
     try:
-        sound = Fusion.loadSound(audio_file)
+        sound = Fusion.from_file(audio_file, format="mp3")
         if query == 'slowed':
             modified_sound = Fusion.effectSlowed(sound, 0.82)
         elif query == 'speedup':