code: def test_plot_util():
      nruns = 4
      logdirs = [
          smoketest(
              "--alg=ppo2 --env=CartPole-v0 --num_timesteps=10000"
          )
          for _ in range(nruns)
      ]
      data = pu.load_results(logdirs)
      assert len(data) == 4
  
      _, axes = pu.plot_results(data[:1])
      assert len(axes) == 1
      _, axes = pu.plot_results(data, tiling="vertical")
      assert axes.shape == (4, 1)
      _, axes = pu.plot_results(data, tiling="horizontal")
      assert axes.shape == (1, 4)
      _, axes = pu.plot_results(data, tiling="symmetric")
      assert axes.shape == (2, 2)
      _, axes = pu.plot_results(data, split_fn=lambda _: "")
      assert len(axes) == 1
  
label_desc: Use image node_id 1 for calling a global function with example usage: test_plot_util() without return types