code: def get_average_cross_validation_fitness(self): # pragma: no cover
          
          avg_cross_validation_fitness = []
          for stats in self.generation_cross_validation_statistics:
              scores = []
              for fitness in stats.values():
                  scores.extend(fitness)
              avg_cross_validation_fitness.append(mean(scores))
  
          return avg_cross_validation_fitness
docs: Get the per-generation average cross_validation fitness.