void SaveBestFit()
    {
        trainings.Sort(new TrainingComparer());

        lastBestFit.Clear();

        for (int i = 0; i < nbToKeep; ++i)
        {
            AIAgent agent = trainings[i].GetComponentInChildren <AIAgent>();
            lastBestFit.Add(agent.GetBrainConfig());
        }

        bestFitness = trainings[0].fitness;
    }