diff --git a/notebooks/1_maze_tuto.ipynb b/notebooks/1_maze_tuto.ipynb
index 2b3b035510..1bec597b68 100644
--- a/notebooks/1_maze_tuto.ipynb
+++ b/notebooks/1_maze_tuto.ipynb
@@ -284,7 +284,7 @@
     "        )\n",
     "        return self._image.figure\n",
     "\n",
-    "    def heuristic(self, s: D.T_State) -> Value[D.T_value]:\n",
+    "    def heuristic(self, s: D.T_state) -> Value[D.T_value]:\n",
     "        \"\"\"Heuristic to be used by search algorithms.\n",
     "\n",
     "        Here Euclidean distance to goal.\n",