Update app.py

app.py

@@ -313,8 +313,8 @@ def inference(audio):
 		contents = fd.read()
 	audio = upload_audio(contents,sample_rate=16000)
 	est_ns = inference_model(audio)
-	note_seq.sequence_proto_to_midi_file(est_ns, './{filename}.mid')
-	return './{filename}.mid'
+	note_seq.sequence_proto_to_midi_file(est_ns, f'./{filename}.mid')
+	return f'./{filename}.mid'
 
 title = "MT3"
 description = "MT3：多任务多音轨音乐转录的 Gradio 演示。要使用它，只需上传音频文件，或点击示例以查看效果。更多信息请参阅下面的链接。"