public static void comparison()
{
ElementId tElem = 50;
ElementId?tN = null;
Assert.Greater(tElem.CompareTo(tN), 0);
Assert.Greater(tElem.CompareTo(25), 0);
Assert.AreEqual(tElem.CompareTo(50), 0);
Assert.Less(tElem.CompareTo(75), 0);
}