added trace

app.py

@@ -19,6 +19,13 @@ def process_image(input_image, model_name, conf):
     print('conf: ')
     print(conf)
     print('start processing: ')
+
+    if model_name is None:
+        model_name = model_names[0]
+
+    if conf is None:
+        conf = 0.6
+
     model_index = model_names.index(model_name)
     print('model_index: ')
     print(model_index)