maybeToExceptT seems like a useful feature.
maybeT2ExceptT :: Functor m => e -> MaybeT m a -> ExceptT e m a and
maybe2ExceptT :: e -> Maybe a -> ExceptT e m a
https://hackage.haskell.org/package/transformers-0.5.6.2/docs/Control-Monad-Trans-Maybe.html#v:maybeToExceptT
maybeToExceptTseems like a useful feature.maybeT2ExceptT :: Functor m => e -> MaybeT m a -> ExceptT e m aandmaybe2ExceptT :: e -> Maybe a -> ExceptT e m ahttps://hackage.haskell.org/package/transformers-0.5.6.2/docs/Control-Monad-Trans-Maybe.html#v:maybeToExceptT