Update app.py

app.py

@@ -10,7 +10,7 @@ synthesis_generator, expression_generator = load_pretrained_model()
 def midi_ddsp_synth(instrument, midi_file):
     '''
     Paras:
-        midi_file: the directory of the midi file
+        midi_file: the path of the midi file
         instrument: instrument type, choose from 'violin', 'viola', 'cello', 'double bass',
                                             'flute', 'oboe', 'clarinet', 'saxophone',
                                             'bassoon', 'trumpet', 'horn', 'trombone', 'tuba'