change mp3 file ab mode to wb mode

app.py

@@ -128,7 +128,7 @@ def download_file(bucket_name, object_key, file_path):
 def polly_text_to_audio(audio_file_name, text, audio_format):
 
     if os.path.exists(audio_file_name):
-        os.remove(response_audio_filename)
+        os.remove(audio_file_name)
         print("output mp3 file deleted successfully.")
     else:
         print("output mp3 file does not exist.")