pub fn be_error(a: Result(a, b)) -> b
pub fn be_error_meta(a: Result(a, b), meta: Meta) -> Nil
pub fn be_false(a: Bool) -> Nil
pub fn be_false_meta(a: Bool, meta: Meta) -> Nil
pub fn be_ok(a: Result(a, b)) -> a
pub fn be_ok_meta(a: Result(a, b), meta: Meta) -> Nil
pub fn be_true(a: Bool) -> Nil
pub fn be_true_meta(a: Bool, meta: Meta) -> Nil
pub fn equal(a: a, b: a) -> Nil
pub fn equal_meta(a: a, b: a, meta: Meta) -> Nil
pub fn evaluate(assertion: Assertion(a, b)) -> Nil
pub fn fail_meta(meta: Meta) -> Nil
pub fn not_equal(a: a, b: a) -> Nil
pub fn not_equal_meta(a: a, b: a, meta: Meta) -> Nil