message: Added comment that None is the batch size
diff: " model.add(tf.keras.layers.LeakyReLU())\n",
  " \n",
  " model.add(tf.keras.layers.Reshape((7, 7, 256)))\n",
  - " assert model.output_shape == (None, 7, 7, 256)\n",
  + " assert model.output_shape == (None, 7, 7, 256) # Note: None is the batch size\n",
  " \n",
  " model.add(tf.keras.layers.Conv2DTranspose(128, (5, 5), strides=(1, 1), padding='same', use_bias=False))\n",
  " assert model.output_shape == (None, 7, 7, 128) \n",
  