docs: private static String sha1hash(Collection<String> nquads) {
          try {
              // create SHA-1 digest
              final MessageDigest md = MessageDigest.getInstance("SHA-1");
              for (final String nquad : nquads) {
                  md.update(nquad.getBytes("UTF-8"));
              }
              return encodeHex(md.digest());
          } catch (final NoSuchAlgorithmException e) {
              throw new RuntimeException(e);
          } catch (final UnsupportedEncodingException e) {
              throw new RuntimeException(e);
          }
      }