code: def test_ComputePosteriorParetoFrontierByTrial(self) -> None:
      # Experiments with batch trials must specify trial_index or data
      with self.assertRaises(UnsupportedError):
          compute_posterior_pareto_frontier(
              self.experiment,
              self.metrics[0],
              self.metrics[1],
              absolute_metrics=[m.name for m in self.metrics],
          )
      pfr = compute_posterior_pareto_frontier(
          self.experiment,
          self.metrics[0],
          self.metrics[1],
          trial_index=0,
          absolute_metrics=[m.name for m in self.metrics],
          num_points=2,
      )
      self.assertIsNone(pfr.arm_names)
  
file_path: Ax/ax/plot/tests/long_running/test_pareto_utils.py
imports: from ax.exceptions.core import UnsupportedError
  from ax.metrics.branin import BraninMetric
  from ax.modelbridge.registry import Models
  from ax.plot.pareto_utils import compute_posterior_pareto_frontier
  from ax.utils.common.testutils import TestCase
  from ax.utils.testing.core_stubs import get_branin_experiment
label_desc: Use image node_id 2 for calling the ComputePosteriorParetoFrontierTest obj's underlying member method code with example usage: obj.test_ComputePosteriorParetoFrontierByTrial() without return types