This package backports the "Control.Monad.Except" module from 'mtl' (if using
'mtl-22.214.171.124' or earlier), which reexports the 'ExceptT' monad transformer and
the 'MonadError' class.
This package should only be used if there is a need to use the
'Control.Monad.Except' module specifically. If you just want the 'mtl' class
instances for 'ExceptT', use 'transformers-compat' instead, since 'mtl-compat'
does nothing but reexport the instances from that package.
Note that unlike how 'mtl-2.2' or later works, the "Control.Monad.Except"
module defined in this package exports all of 'ExceptT''s monad class
instances. Therefore, you may have to declare 'import Control.Monad.Except ()'
at the top of your file to get all of the 'ExceptT' instances in scope.