public static IEnumerable<int> SomeMethod<T>(this IEnumerable<T> list, Func<T, int> someAction, int percentline)
        {
            IEnumerable<T> count = list.OrderByDescending(someAction).Take((int)(list.Count() * percentline / 100.0f));
            try
            {
                if (list.Count() <= 100 && list.Count() >= 1)
                {
                    //IEnumerable<T> count = list.OrderByDescending(someAction).Take((int)(list.Count() * percentline / 100.0f));
                    _ = count;
                    Console.WriteLine("Перечень элементов: \n" + string.Join("\n", count));
                }
                else
                {
                    throw new ArgumentException();
                }
            }
            catch (ArgumentException)
            {
                Console.Write("ОШИБКА!!!\n");
            }
            //return (IEnumerable<int>)list;
            return count(T);
        }public static IEnumerable<int> ExtensionMethod<T>(this IEnumerable<T> list, Func<T, int> someAction, int percentline)
        {            
            try
            {
                if (list.Count() <= 100 && list.Count() >= 1)
                {
                    IEnumerable<T> count = list.OrderByDescending(someAction).Take((int)(list.Count() * percentline / 100.0f));
                    Console.WriteLine("Перечень элементов: \n" + string.Join("\n", count));
                }
                else
                {
                    throw new ArgumentException();
                }
            }
            catch (ArgumentException)
            {
                Console.Write("ОШИБКА!!!\n");
            }
            // ошибка... как поправить?
            return (IEnumerable<int>)list;
        }public void Search(Node value)
        {
            if (_root.Salary.Equals(value))
            {
                if (_root.Left != null)
                    return;
            }
            else
            {
                if (_root.Right != null)
                    return;
            }
        }