public static void TestFindAll <T, TCollection, TPredicate>(
     List2D <T> list, TPredicate match, TCollection expected)
     where TCollection : ICollection <T>, new()
     where TPredicate : struct, IPredicate <T>
 => CollectionAssert.AreEqual(
     expected, list.FindAll <TCollection, TPredicate>(match));
 public static void TestFindAll <T, TCollection>(
     List2D <T> list, Predicate <T> match, TCollection expected)
     where TCollection : ICollection <T>, new()
 => CollectionAssert.AreEqual(expected, list.FindAll <TCollection>(match));