class_docstr: Takes the mean of the best models, where the models are ranked according to
  the value of an evaluation metric.
code: def requires_training(self):
      return True
  
imports: from abc import abstractmethod
  from collections import OrderedDict
  import copy
  import logging
  from typing import List, Optional, Union
  import numpy
  from merlion.evaluate.anomaly import TSADMetric
  from merlion.evaluate.forecast import ForecastMetric
  from merlion.utils import UnivariateTimeSeries, TimeSeries
  from merlion.utils.misc import AutodocABCMeta
label_desc: Use image node_id 3 for calling the ModelSelector obj's underlying member method code with example usage: obj.requires_training() and returns: True