diff --git a/18_reinforcement_learning.ipynb b/18_reinforcement_learning.ipynb
index ba2379a..a2b20a5 100644
--- a/18_reinforcement_learning.ipynb
+++ b/18_reinforcement_learning.ipynb
@@ -2547,12 +2547,12 @@
    "source": [
     "def lander_render_policy_net(model, n_max_steps=500, seed=42):\n",
     "    frames = []\n",
-    "    env = gym.make(\"LunarLander-v2\")\n",
+    "    env = gym.make(\"LunarLander-v2\", render_mode=\"rgb_array\")\n",
     "    tf.random.set_seed(seed)\n",
     "    np.random.seed(seed)\n",
     "    obs, info = env.reset(seed=seed)\n",
     "    for step in range(n_max_steps):\n",
-    "        frames.append(env.render(mode=\"rgb_array\"))\n",
+    "        frames.append(env.render())\n",
     "        probas = model(obs[np.newaxis])\n",
     "        logits = tf.math.log(probas + tf.keras.backend.epsilon())\n",
     "        action = tf.random.categorical(logits, num_samples=1)\n",