function getLastAssociative() {
	return makeAssociative(y => x => (O.isNone(x) ? x : y));
}
`Associative` returning the left-most non-`None` value

| x       | y       | combine(y)(x) |
| ------- | ------- | ------------- |
| none    | none    | none          |
| some(a) | none    | some(a)       |
| none    | some(a) | some(a)       |
| some(a) | some(b) | some(a)       |