public void publicKey(PGPPublicKey publicKey) {
        }
    }

    private static class FingerprintListCacheEntrySerializer extends AbstractSerializer<CacheEntry<List<Fingerprint>>> {
        private final ListSerializer<Fingerprint> listSerializer;

        public FingerprintListCacheEntrySerializer(ListSerializer<Fingerprint> listSerializer) {
            this.listSerializer = listSerializer;
        }