diff --git a/02_end_to_end_machine_learning_project.ipynb b/02_end_to_end_machine_learning_project.ipynb
index 79bee1d..8a148cd 100644
--- a/02_end_to_end_machine_learning_project.ipynb
+++ b/02_end_to_end_machine_learning_project.ipynb
@@ -911,7 +911,7 @@
     "        self.add_bedrooms_per_room = add_bedrooms_per_room\n",
     "    def fit(self, X, y=None):\n",
     "        return self  # nothing else to do\n",
-    "    def transform(self, X, y=None):\n",
+    "    def transform(self, X):\n",
     "        rooms_per_household = X[:, rooms_ix] / X[:, households_ix]\n",
     "        population_per_household = X[:, population_ix] / X[:, households_ix]\n",
     "        if self.add_bedrooms_per_room:\n",