docs: public int importKeysAndEncrypt(final List<ECKey> keys, KeyParameter aesKey) {
          // TODO: Firstly check if the aes key can decrypt any of the existing keys successfully.
          checkState(keyCrypter != null, "Not encrypted");
          LinkedList<ECKey> encryptedKeys = Lists.newLinkedList();
          for (ECKey key : keys) {
              if (key.isEncrypted())
                  throw new IllegalArgumentException("Cannot provide already encrypted keys");
              encryptedKeys.add(key.encrypt(keyCrypter, aesKey));
          }
          return importKeys(encryptedKeys);
      }