diff --git a/sysidentpy/model_structure_selection/meta_model_structure_selection.py b/sysidentpy/model_structure_selection/meta_model_structure_selection.py
index 09152423..848f356e 100644
--- a/sysidentpy/model_structure_selection/meta_model_structure_selection.py
+++ b/sysidentpy/model_structure_selection/meta_model_structure_selection.py
@@ -360,7 +360,7 @@ def evaluate_objective_function(
         X_test: Optional[np.ndarray],
         y_test: Optional[np.ndarray],
         population: np.ndarray,
-    ) -> list[float]:
+    ):
         """Fit the polynomial NARMAX model.
 
         Parameters