code: def test_is_actuator_base_subclass(self):
      assert issubclass(LinearSpring, ActuatorBase)
  
imports: import pytest
  from sympy import S, Matrix, Symbol, SympifyError, sqrt
  from sympy.physics.mechanics import ActuatorBase, Force, ForceActuator, KanesMethod, LinearDamper, LinearPathway, LinearSpring, Particle, PinJoint, Point, ReferenceFrame, RigidBody, TorqueActuator, Vector, dynamicsymbols
  from sympy.core.expr import Expr
label_desc: Use image node_id 3 for calling the TestLinearSpring obj's underlying member method code with example usage: obj.test_is_actuator_base_subclass() without return types