@sig(H/ "b" >> (H/ "a" >> "b") >> t(Maybe, "a") >> "b")
def maybe(default, f, maybe_a):
    return default if maybe_a == Nothing else f(maybe_a[0])
maybe :: b -> (a -> b) -> Maybe a -> b
dataset/ETHPy150Open billpmurphy/hask/hask/Data/Maybe.py/maybe