diff --git a/Notebooks/Chap15/15_1_GAN_Toy_Example.ipynb b/Notebooks/Chap15/15_1_GAN_Toy_Example.ipynb
index 4f18380..c8b7895 100644
--- a/Notebooks/Chap15/15_1_GAN_Toy_Example.ipynb
+++ b/Notebooks/Chap15/15_1_GAN_Toy_Example.ipynb
@@ -4,7 +4,6 @@
   "metadata": {
     "colab": {
       "provenance": [],
-      "authorship_tag": "ABX9TyM0StKV3FIZ3MZqfflqC0Rv",
       "include_colab_link": true
     },
     "kernelspec": {
@@ -339,7 +338,7 @@
         "    print(\"Initial generator loss = \", compute_generator_loss(z, theta, phi0, phi1))\n",
         "    for iter in range(n_iter):\n",
         "      # Get gradient\n",
-        "      dl_dtheta = compute_generator_gradient(x_real, x_syn, phi0, phi1)\n",
+        "      dl_dtheta = compute_generator_gradient(z, theta, phi0, phi1)\n",
         "      # Take a gradient step (uphill, since we are trying to make synthesized data less well classified by discriminator)\n",
         "      theta = theta + alpha * dl_dtheta ;\n",
         "\n",