code: def pareto_set(self) -> Sequence[AbstractEnsemble]:
      if not hasattr(self, "pareto_set_"):
          raise NotFittedError(
              "`pareto_set` not created, please call `fit()` first"
          )
      return self.pareto_set_
  
imports: from __future__ import annotations
  from typing import Sequence
  import warnings
  import numpy
  from sklearn.exceptions import NotFittedError
  from autosklearn.automl_common.common.utils.backend import Backend
  from autosklearn.constants import TASK_TYPES
  from autosklearn.data.validation import SUPPORTED_FEAT_TYPES
  from autosklearn.ensemble_building.run import Run
  from autosklearn.ensembles.abstract_ensemble import AbstractEnsemble, AbstractMultiObjectiveEnsemble
  from autosklearn.ensembles.singlebest_ensemble import SingleModelEnsemble
  from autosklearn.metrics import Scorer, calculate_losses
  from autosklearn.pipeline.base import BasePipeline
  from autosklearn.util.multiobjective import pareto_front
label_desc: Use image node_id 2 for calling the MultiObjectiveDummyEnsemble obj's underlying member method code with example usage: obj.pareto_set() and returns: self