Update app.py

app.py

@@ -40,7 +40,7 @@ def make_prediction(file_name=None, detection_threshold=0.3):
     else:
         return "You must provide an input audio file."
     
-    if detection_threshold != '':
+    if detection_threshold is not None and detection_threshold != '':
         args['detection_threshold'] = float(detection_threshold)
     
     results = du.process_file(audio_file, model, params, args, max_duration=5.0)