(let
  sum = fun sum (x : int list) : int => (case x of nil => 0 | h::t => h+(sum t))
in
  (sum (1::2::3::4::5::6::7::(nil[int]))) + 
  (sum (5::4::10::27::34::17::0::(nil[int]))) +
  (sum (nil[int])) + 
  (sum (100::0::42::314::5::19::(nil[int])))
end);