code: def test_trajectory(example):
      model, args = example
      q_f, p_f, _, _ = velocity_verlet(
          args.q_i,
          args.p_i,
          model.potential_fn,
          model.kinetic_grad,
          args.step_size,
          args.num_steps,
      )
      logger.info("initial q: {}".format(args.q_i))
      logger.info("final q: {}".format(q_f))
      assert_equal(q_f, args.q_f, args.prec)
      assert_equal(p_f, args.p_f, args.prec)
  
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 2 for calling a global function with example usage: test_trajectory(example) without return types