How to deal with nested records and listA arrows
[YS {ser = "MSG"
        , ori =[YO {site = "Bordeaux" , perfM = ["0","0"]  }
               ,YO {site = "Paris"    , perfM = ["1","1"]}]}
    ,YS {ser = "OTP"
        , ori =[YO {site = "Marseilles" , perfM = ["20","20"]}
               ,YO {site = "Lyon"       , perfM = ["21","21"]}]}
    ]

[YS {ser = "MSG"
        , ori = [YO {site = "Bordeaux", perfM = ["0"]}
                ,YO {site = "Paris", perfM =["1"]}
                ,YO {site = "Bordeaux", perfM = ["0","0"]}
                ,YO {site = "Paris", perfM = ["1","1"]}]}
    ,YS {ser = "OTP"
        , ori = [YO {site = "Marseilles"
                , perfM = ["20"]}
                ,YO {site = "Lyon", perfM =["21"]}
                ,YO {site = "Marseilles", perfM = ["20","20"]}
                ,YO {site = "Lyon", perfM = ["21","21"]}]}
    ]

addScen :: YScen -> [YScen] -> YScen
        addScen sc [] = sc
        addScen sc (x:xs)
                    | ser sc == ser x
                                = YS {ser=ser sc
                                     ,ori=(ori sc) }
                                    -- ,ori=(ori x) ++ (ori sc) <--- Error
                    | otherwise = addScen sc xs