class_docstr: The optimal recommender makes recommendations by accessing the true
  performances of the models.
class_docstr_tok: ["The","optimal","recommender","makes","recommendations","by","accessing","the","true","performances","of","the","models","."]
code: def _get_performances(
      self, configs: List[Config[ModelConfig]]
  ) -> List[Performance]:
      return [self.tracker.get_performance(c) for c in configs]
  
file_path: gluonts/src/gluonts/nursery/tsbench/src/tsbench/recommender/optimal.py
imports: from typing import List, Optional
  from tsbench.config import Config, ModelConfig
  from tsbench.evaluations.metrics import Performance
  from tsbench.evaluations.tracking import ModelTracker
  from ._base import Recommender
  from ._factory import register_recommender
  from .generator import CandidateGenerator
label_desc: Use image node_id 2 for calling the OptimalRecommender obj's underlying member method code with example usage: obj._get_performances(configs) and returns: unknown