public string CandidateInfo(Candidate candidate)
 {
     return($"X1 = {candidate.X1}, \n" +
            $"X2 = {candidate.X2}, \n" +
            $"X3 = {candidate.X3}, \n" +
            $"Fitness = {candidate.Fitness}, \n" +
            $"Average of Generation = {CurrentGeneration.Select(x => x.Fitness).Average()}\n");
 }