docstr: Return validation performance of ensemble.
  
  Returns
  -------
  float
docstr_tok: ["Return","validation","performance","of","ensemble",".","Returns","--","--","--","-","float"]
code: def get_validation_performance(self) -> float:
      """Return validation performance of ensemble.
  
      Returns
      -------
      float
      """
  
imports: from __future__ import annotations
  from abc import ABC, abstractmethod
  from typing import Any, Dict, List, Sequence, Tuple, Union
  import numpy
  from autosklearn.automl_common.common.utils.backend import Backend
  from autosklearn.data.validation import SUPPORTED_FEAT_TYPES
  from autosklearn.ensemble_building.run import Run
  from autosklearn.metrics import Scorer
  from autosklearn.pipeline.base import BasePipeline
label_desc: Use image node_id 8 for calling the AbstractEnsemble obj's underlying member method code with example usage: obj.get_validation_performance() without return types