diff --git a/tutorials/notebooks/intro_gfn_smiley.ipynb b/tutorials/notebooks/intro_gfn_smiley.ipynb
index 8a6ad63b..68279cc0 100644
--- a/tutorials/notebooks/intro_gfn_smiley.ipynb
+++ b/tutorials/notebooks/intro_gfn_smiley.ipynb
@@ -1708,7 +1708,7 @@
     "        # Then, we remove any done action, and also the exit action.\n",
     "        states.set_nonexit_action_masks(states.tensor == 1, allow_exit=False)\n",
     "\n",
-    "        if env.mask_invalid_actions:\n",
+    "        if self.mask_invalid_actions:\n",
     "            # Now we remove invalid actions. Here we are enforcing that\n",
     "            # only one left eyebrow, one right eyebrow, and one smile can be\n",
     "            # selected. 0 = not allowed.\n",
@@ -1746,7 +1746,7 @@
     "            + 1 if the face is frowny. :(\n",
     "            + 2 if the face is smiley. :)\n",
     "        \"\"\"\n",
-    "        if not env.mask_invalid_actions:\n",
+    "        if not self.mask_invalid_actions:\n",
     "            # Tensor organization is [left_eb *2, right_eb * 2, mouth * 2]\n",
     "            valid = torch.zeros(states.batch_shape + (3,))\n",
     "            valid[..., 0] = states.tensor[..., :2].sum(-1) == 1  # One left eyebrow.\n",
@@ -1759,7 +1759,7 @@
     "        rewards[states.tensor[..., 4] == 1] = torch.tensor([2])  # Smiles.\n",
     "        rewards[states.tensor[..., 5] == 1] = torch.tensor([1])  # Frowns.\n",
     "\n",
-    "        if not env.mask_invalid_actions:\n",
+    "        if not self.mask_invalid_actions:\n",
     "            rewards = rewards * valid  # This will remove any double mouths.\n",
     "\n",
     "        return rewards.squeeze()\n",