code: public List<SessionTicketKey> parseBytes(byte[] json) throws IOException {
          List<String> allSeeds = TicketSeeds.parseFromJSONBytes(json, objectMapper).getAllSeeds();
          return allSeeds.stream().map(this::deriveKeyFromSeed).collect(Collectors.toList());
      }
docs: Returns a list of tickets parsed from the given JSON bytes. The keys are returned in a format suitable for
  use with netty. The first keys are the current keys, following that are the new keys and old keys.
  
  @param json the JSON bytes containing ticket seed data.
  @return a list of ticket keys. Current keys are first, then new keys, then old keys.
  @throws IOException if parsing the JSON fails.
  @throws IllegalArgumentException if the JSON does not contain any current seeds.