// Extend above example to sanity check input.
local equal_parts(size, ingredients) =
  local qty = size / std.length(ingredients);
  // Check a pre-condition
  if std.length(ingredients) == 0 then
    error 'Empty ingredients.'
  else [
    { kind: i, qty: qty }
    for i in ingredients
  ];

local subtract(a, b) =
  assert a > b : 'a must be bigger than b';
  a - b;

assert std.isFunction(subtract);

{
  test1: equal_parts(1, ['Whiskey']),
  test2: subtract(10, 3),
  object: {
    assert self.f < self.g : 'wat',
    f: 1,
    g: 2,
  },
  assert std.isObject(self.object),
}