diff --git a/rocketpy/mathutils/function.py b/rocketpy/mathutils/function.py
index 731fc7810..9dd9ebdf3 100644
--- a/rocketpy/mathutils/function.py
+++ b/rocketpy/mathutils/function.py
@@ -366,8 +366,7 @@ def linear_interpolation(x, x_min, x_max, x_data, y_data, coeffs):
         elif interpolation == 1:  # polynomial
 
             def polynomial_interpolation(x, x_min, x_max, x_data, y_data, coeffs):
-                y = np.sum(coeffs * x ** np.arange(len(coeffs)))
-                return y
+                return np.sum(coeffs * x ** np.arange(len(coeffs)))
 
             self._interpolation_func = polynomial_interpolation