diff --git a/lessons/3-NeuralNetworks/03-Perceptron/Perceptron.ipynb b/lessons/3-NeuralNetworks/03-Perceptron/Perceptron.ipynb
index 2928fa0a..a398b309 100644
--- a/lessons/3-NeuralNetworks/03-Perceptron/Perceptron.ipynb
+++ b/lessons/3-NeuralNetworks/03-Perceptron/Perceptron.ipynb
@@ -636,6 +636,7 @@
     "# If you are not running this notebook from a cloned repository, you may need to grab the binary dataset file first\n",
     "# !wget https://github.com/microsoft/AI-For-Beginners/blob/main/data/mnist.pkl.gz?raw=true\n",
     "# In this case correct the link to the dataset below as well.\n",
+    "# by liuyh : If it does not work , check this post : https://github.com/microsoft/AI-For-Beginners/issues/241"
     "\n",
     "with gzip.open('../../data/mnist.pkl.gz', 'rb') as mnist_pickle:\n",
     "    MNIST = pickle.load(mnist_pickle)"