Expands a Map[K1, Iterable[K2]] into the original
Iterable[K] by joining every instance of K2 in each
Iterable[K2] with its corresponding instance of K1 and
calling dec
on each pair.
Expands a Map[K1, Iterable[K2]] into the original
Iterable[K] by joining every instance of K2 in each
Iterable[K2] with its corresponding instance of K1 and
calling dec
on each pair.
Curries the supplied fn of K into a nested function
of K1 then K2 using the inversion of pivot
.