diff --git a/nbs/core.ipynb b/nbs/core.ipynb
index 047d83f60..0d23f478f 100644
--- a/nbs/core.ipynb
+++ b/nbs/core.ipynb
@@ -636,10 +636,8 @@
     "        # Add predictions to forecasts DataFrame\n",
     "        if isinstance(self.uids, pl_Series):\n",
     "            fcsts = pl_DataFrame(fcsts, schema=cols)\n",
-    "            df_constructor = pl_DataFrame\n",
     "        else:\n",
     "            fcsts = pd.DataFrame(fcsts, columns=cols)\n",
-    "            df_constructor = pd.DataFrame\n",
     "        fcsts_df = horizontal_concat([fcsts_df, fcsts])\n",
     "\n",
     "        # Add original input df's y to forecasts DataFrame    \n",
diff --git a/neuralforecast/core.py b/neuralforecast/core.py
index 4c20dc0f4..4d7bca12b 100644
--- a/neuralforecast/core.py
+++ b/neuralforecast/core.py
@@ -572,10 +572,8 @@ def cross_validation(
         # Add predictions to forecasts DataFrame
         if isinstance(self.uids, pl_Series):
             fcsts = pl_DataFrame(fcsts, schema=cols)
-            df_constructor = pl_DataFrame
         else:
             fcsts = pd.DataFrame(fcsts, columns=cols)
-            df_constructor = pd.DataFrame
         fcsts_df = horizontal_concat([fcsts_df, fcsts])
 
         # Add original input df's y to forecasts DataFrame