Minor bug fix

app.py

@@ -73,6 +73,9 @@ def run(
     """
     if arrival_date:
         arrival_date_input = datetime.datetime.fromtimestamp(arrival_date).strftime("%m-%d-%Y")
+    else:
+        arrival_date_input = None
+
     logger.info(
         f'Origin: {origin}, Destination: {destination}, Arrival Date: {arrival_date_input}, Age: {age}, Duration: {trip_duration},'
         f' Interests: {interests}, Cuisines: {cuisine_preferences}, Children: {children}, Daily Budget: {budget}'