def select(self):
        parent_pool = []
        fitness_sum = 0
        for elem in self.fitness_list:
            fitness_sum += elem
        for i in range(0, len(self.population), 1):
            roulette_pointer = random.uniform(0, fitness_sum)
            cur_sum = 0
            for j in range(0, len(self.fitness_list), 1):
                cur_sum += self.fitness_list[j]
                if cur_sum > roulette_pointer:
                    lucky_one = j
                    break
            parent_pool.append(self.population[lucky_one])
        return parent_pool