A.I
let (<$>): ('a => 'b) => Monad.t('a) => Monad.t('b);
let (<#>): Monad.t('a) => ('a => 'b) => Monad.t('b);
let (<*>): Monad.t(('a => 'b)) => Monad.t('a) => Monad.t('b);