Update app.py

app.py

@@ -41,8 +41,10 @@ def post():
 @app.route('/messages', methods=['POST'])
 def messages():
     roomidInput = flask.request.get_json()['roomIdInput']
-    return flask.jsonify(rooms[roomidInput])
-
+    if roomidInput in rooms:
+        return flask.jsonify(rooms[roomidInput])
+    else:
+        return flask.jsonify({"message": "room does not exist"})
 
 
 if __name__ == "__main__":