public void ListExtend() { var src = list(1, 2, 3, 4, 5); var f = func((Lst <int> x) => Lst.foldl(operators.add, 0, x)); var result = Lst.Extend <int, int>().extend(f)(src); var expect = list(15, 14, 12, 9, 5); claim.equal(expect, result); }