code: def _trial_to_values(t: FrozenTrial) -> Tuple[float, ...]:
      assert t.values is not None
      return tuple(t.values)
  
file_path: optuna/tests/test_multi_objective.py
imports: from typing import Tuple
  from optuna import create_study
  from optuna.study._multi_objective import _get_pareto_front_trials_2d
  from optuna.study._multi_objective import _get_pareto_front_trials_nd
  from optuna.trial import FrozenTrial
label_desc: Use image node_id 1 for calling a global function with example usage: _trial_to_values(t) and returns: tuple