The MaybeT transformer is defined as: newtype MaybeT m a = MaybeT {runMaybeT :: m (Maybe http://haskell.org/ghc/docs/latest/html/libraries/base/Prelude.html#t:Maybe a)} instance Functor http://haskell.org/ghc/docs/latest/html/libraries/base/Prelude.html#t:Functo... m => Functor http://haskell.org/ghc/docs/latest/html/libraries/base/Prelude.html#t:Functo... (MaybeT m) where fmap http://haskell.org/ghc/docs/latest/html/libraries/base/Prelude.html#v:fmap f x = MaybeT $ http://haskell.org/ghc/docs/latest/html/libraries/base/Prelude.html#v:. fmap http://haskell.org/ghc/docs/latest/html/libraries/base/Prelude.html#v:fmap (fmap http://haskell.org/ghc/docs/latest/html/libraries/base/Prelude.html#v:fmap f) $ http://haskell.org/ghc/docs/latest/html/libraries/base/Prelude.html#v:. runMaybeT x .... Question: What does "runMaybeT x" mean? Thanks, Daryoush