private void btnCalculate_Click(object sender, EventArgs e)
        {
            foreach (var animal in _animals)
            {
                if (!_train.GetWagon().Any())
                {
                    CreateWagon(animal);
                    continue;
                }

                var canEnter = false;
                foreach (var wagon in _train.GetWagon())
                {
                    canEnter = wagon.CheckRules(animal);
                    if (canEnter)
                    {
                        wagon.AddAnimal(animal);
                        listBox2.Items.Add(wagon.ToString());
                        break;
                    }
                }

                if (!canEnter)
                {
                    CreateWagon(animal);
                }
            }

            listBox2.DataSource = _train.GetWagon();
        }