How to Log Exception in errorHandler of Yesod

yesod_errorHandler_logging

instance Yesod App where

    errorHandler (InternalError e) = do
        $(logWarn) e
        applyLayout "My Internal Server Error." [hamlet| <h1> my internal server error|] 
      where applyLayout :: Yesod master => Html -> HtmlUrl (Route master) -> GHandler sub master ChooseRep
            applyLayout title body = fmap chooseRep $ defaultLayout $ do
              setTitle title
              toWidget body