code: def test_time_reversibility(example):
      model, args = example
      q_forward, p_forward, _, _ = velocity_verlet(
          args.q_i,
          args.p_i,
          model.potential_fn,
          model.kinetic_grad,
          args.step_size,
          args.num_steps,
      )
      p_reverse = {key: -val for key, val in p_forward.items()}
      q_f, p_f, _, _ = velocity_verlet(
          q_forward,
          p_reverse,
          model.potential_fn,
          model.kinetic_grad,
          args.step_size,
          args.num_steps,
      )
      assert_equal(q_f, args.q_i, 1e-5)
  
imports: import logging
  from collections import namedtuple
  import pytest
  import torch
  from pyro.ops.integrator import velocity_verlet
  from tests.common import assert_equal
label_desc: Use image node_id 4 for calling a global function with example usage: test_time_reversibility(example) without return types