Hello! I am trying to simulate a simple mass and spring system and to evaluate the natural frequencies with the command Poles from Modelica_LinearSystems2 library, but it says: Class Poles not found in scope.. my code is the following one:

model test2
import Modelica_LinearSystems2;
  //import Modelica_LinearSystems2.ZerosAndPoles;
  Modelica.Mechanics.Rotational.Components.Inertia inertia1 annotation(Placement(visible = true, transformation(origin = {-76, 12}, extent = {{-10, -10}, {10, 10}}, rotation = 0)));
  Modelica.Mechanics.Rotational.Components.Spring spring1 annotation(Placement(visible = true, transformation(origin = {-48, 10}, extent = {{-10, -10}, {10, 10}}, rotation = 0)));
  Modelica.Mechanics.Rotational.Components.Inertia inertia2 annotation(Placement(visible = true, transformation(origin = {-16, 12}, extent = {{-10, -10}, {10, 10}}, rotation = 0)));
equation
  connect(spring1.flange_b, inertia2.flange_a) annotation(Line(points = {{-38, 10}, {-26, 10}, {-26, 12}, {-26, 12}}));
  connect(inertia1.flange_b, spring1.flange_a) annotation(Line(points = {{-66, 12}, {-58, 12}, {-58, 10}, {-58, 10}}));
  annotation(uses(Modelica(version = "3.2.2")));
//linearize(A,stopTime=2);
Poles();
end test2;


Thank you in advance for the response