code: def test_valid_constructor_without_reaction(
      self, torque, target_frame
  ):
      instance = TorqueActuator(torque, self.axis, target_frame)
      assert isinstance(instance, TorqueActuator)
  
      assert hasattr(instance, "torque")
      assert isinstance(instance.torque, ExprType)
      assert instance.torque == torque
  
      assert hasattr(instance, "axis")
      assert isinstance(instance.axis, Vector)
      assert instance.axis == self.axis
  
      assert hasattr(instance, "target_frame")
      assert isinstance(instance.target_frame, ReferenceFrame)
      assert instance.target_frame == target.frame
  
      assert hasattr(instance, "reaction_frame")
      assert instance.reaction_frame is None
  
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 4 for calling the TestTorqueActuator obj's underlying member method code with example usage: obj.test_valid_constructor_without_reaction(torque, target_frame) without return types