using System.Collections.Generic;
using System.Linq;
using System.Console;

module Program
{
  Main() : void
  {
    def l = [1, 2, 3, 4, 5];
    def r = l.Where(i=> i%2 ==0);
    WriteLine($"..$r");
    def r = l.Where2(i=> i%2 ==0);
    WriteLine($"..$r");
    def r = l.Where3(i=> i%2 ==0);
    WriteLine($"..$r");
  }
}
/*
REFERENCE: external-extension-method-lib

BEGIN-OUTPUT
2, 4
2, 4
2, 4
END-OUTPUT
*/