data ErrorMsg : TypeCouldNotParse : String -> ErrorMsgMissingOption : String -> ErrorMsgMissingArgument : ErrorMsgOptionSetTwice : String -> ErrorMsgTooManyArguments : ErrorMsgMissingOptArg : String -> ErrorMsgShow ErrorMsgdata Error : Type -> TypethrowE : ErrorMsg -> Error afromEither : Either ErrorMsg a -> Error a(>>=) : Error a -> (a -> Error b) -> Error bexitWith : List1 ErrorMsg -> IO a