a75735ba73983c48638bbe52d77997f24075a043,optuna/storages/_base.py,BaseStorage,get_best_trial,#BaseStorage#Any#,564

Before Change

        if len(all_trials) == 0:
            raise ValueError("No trials are completed yet.")

        if self.get_study_direction(study_id) == StudyDirection.MAXIMIZE:
            best_trial = max(all_trials, key=lambda t: t.value)
        else:
            best_trial = min(all_trials, key=lambda t: t.value)

After Change

        if len(all_trials) == 0:
            raise ValueError("No trials are completed yet.")

        direction = self.get_study_direction(study_id)
        if len(direction) > 1:
            raise ValueError("Best trial can be obtained only for single-objective optimization.")
        direction = direction[0]

        if direction == StudyDirection.MAXIMIZE:
            best_trial = max(all_trials, key=lambda t: t.value)
        else:

Instances