Update app.py

app.py

@@ -146,7 +146,7 @@ def GenerateMIDI(progress=gr.Progress()):
           
     while itrack < len(opus):
         for event in opus[itrack]:
-            if event[0] == 'note_on' or event[0] == 'note_off': 
+            if (event[0] == 'note_on') or (event[0] == 'note_off'): 
                 output1.append(event)
         itrack += 1