Update app.py

if no in dict -> 0

app.py

@@ -16,7 +16,7 @@ def greet(name):
 def classify_image(img):
   pred, idx, probs = learn.predict(img)
   return {
-      price: str(prices[pred]) + ' baht (' + pred + ")",
+      price: str(prices[pred] if pred in prices else 0) + ' baht (' + pred + ")",
       label: dict(zip(learn.dls.vocab, map(float, probs))),
   }