(defn sedols [xs]
(letfn [(sedol [ys] (let [weights [1 3 1 7 3 9]
convtonum (map #(Character/getNumericValue %) ys)
check (-> (reduce + (map * weights convtonum)) (rem 10) (->> (- 10)) (rem 10))]
(str ys check)))]
(map #(sedol %) xs)))