new_contents: class Validator(object):
      """
      Evaluates configuration on a given set of instances.
      """
  
      def __init__(self, scenario, tae, runhistory):
          """
          Create validator to run configurations on instances and create a
          cost/performance-table in runhistory.
          """
          self.scen = scenario
          self.tae = tae
          self.runhistory = runhistory
  
      def run(self, conf, repetition=1):
          """
          Run configuration on instances from scenario to evaluate it.
  
          Parameters
          ----------
          conf: Configuration
              configuration to be evaluated
          repetitions: int
              number of repetitions (relevant for non-deterministic algorithms)
          """
          raise NotImplementedError()
          instances = self.scen.train_insts
          for r in range(repetition):
              seed = 42 # TODO rng needed
              for i in instances:
                  self.tae.start(conf, i, self.scen.cutoff, seed,
                                 self.scen.train_insts[i],
                                 capped=False)
  
subject: ADD sketch of validator