Make2.LiftLifts functions into the monad.
A function that operates on values can be mapped to a function that operates on computations. We provide several liftes for common arities.
val nullary : 'a -> ('a, 'e) T2(M).tnullary x lifts x (a synonym to return)
binary f lifts f
val ternary :
('a -> 'b -> 'c -> 'd) ->
('a, 'e) T2(M).t ->
('b, 'e) T2(M).t ->
('c, 'e) T2(M).t ->
('d, 'e) T2(M).tternary f lifts f