let main () : unit Deferred.t =
let kvs = [
("one", "uno");
("two", "dos");
("three", "tres");
("four", "cuatro");
] in
let db = LevelDB.open_db "/tmp/foo" in
put_all db kvs >>= fun () ->
get db "one" >>= fun v ->
print_endline (Option.value v ~default:"not found");
LevelDB.close db;
return ()