diff --git a/courses/ml1/lesson1-rf.ipynb b/courses/ml1/lesson1-rf.ipynb
index 0499e974e..779b4354d 100644
--- a/courses/ml1/lesson1-rf.ipynb
+++ b/courses/ml1/lesson1-rf.ipynb
@@ -3490,7 +3490,7 @@
    },
    "outputs": [],
    "source": [
-    "df_trn, y_trn = proc_df(df_raw, 'SalePrice')\n",
+    "df_trn, y_trn, nas = proc_df(df_raw, 'SalePrice')\n",
     "X_train, X_valid = split_vals(df_trn, n_trn)\n",
     "y_train, y_valid = split_vals(y_trn, n_trn)"
    ]
diff --git a/courses/ml1/lesson2-rf_interpretation.ipynb b/courses/ml1/lesson2-rf_interpretation.ipynb
index d7eccce43..91066e513 100644
--- a/courses/ml1/lesson2-rf_interpretation.ipynb
+++ b/courses/ml1/lesson2-rf_interpretation.ipynb
@@ -3434,7 +3434,7 @@
     "df_ext = df_keep.copy()\n",
     "df_ext['is_valid'] = 1\n",
     "df_ext.is_valid[:n_trn] = 0\n",
-    "x, y = proc_df(df_ext, 'is_valid')"
+    "x, y, nas = proc_df(df_ext, 'is_valid')"
    ]
   },
   {