using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

        IEnumerable<string> timeSeries = null;

        var samplesTimeSeries = timeSeries == null ? new string[0] : timeSeries as string[] ?? timeSeries.ToArray();

        if (!samplesTimeSeries.Any())

        {

            Console.WriteLine("I'm null");

        }       

        Console.WriteLine("Hello World");

    }

}