Trans.S2
Binary to binary monad transfomer
type ('a, 'e) t
type ('a, 'e) m
type ('a, 'e) e
val lift : ('a, 'e) m -> ('a, 'e) t
lifts inner monad into the resulting monad
val run : ('a, 'e) t -> ('a, 'e) e
runs the computation