e e : ls) =
    let (rs, es) = getErrors ls
    in (rs, e:es)
getErrors (l:ls) =
   
getErrors (UnknownLexeme e : ls) =
    let (rs, es) = getErrors ls
    in (rs, e:es)
getErrors (UnknownLexeme e : ls) =
    let (rs, es) = getErrors ls
    in (rs, e:es)