code: def test_to_loads(self):
      self.pB.set_pos(self.pA, self.q * self.N.x)
      spring = LinearSpring(self.stiffness, self.pathway, self.l)
      normal = self.q / sqrt(self.q**2) * self.N.x
      pA_force = self.stiffness * (sqrt(self.q**2) - self.l) * normal
      pB_force = -self.stiffness * (sqrt(self.q**2) - self.l) * normal
      expected = [Force(self.pA, pA_force), Force(self.pB, pB_force)]
      loads = spring.to_loads()
  
      for load, (point, vector) in zip(loads, expected):
          assert isinstance(load, Force)
          assert load.point == point
          assert (load.vector - vector).simplify() == 0
  
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 10 for calling the TestLinearSpring obj's underlying member method code with example usage: obj.test_to_loads() without return types