subsBinding fname (b@(BVar name):bs) (e:es) ex = do
    subs' <- (subs ex name e)
    subsBinding fname bs es subs'
subsBinding fname (b@(BVar name):bs) (e:es) ex = do
    subs' <- (subs ex name e)
    subsBinding fname bs es subs'
subsBinding fname (b@(BVar name):bs) (e:es) ex = do
    subs' <- (subs ex name e)
    subsBinding fname bs es subs'