docs: @SuppressWarnings("unused")
      private Map<String, String> hashFiles(String... fileNames) {
          Map<String, String> hashes = new HashMap<String, String>();
          for (int i = 0; i < fileNames.length; i++) {
              String hash = hashURL(fileNames[i]);
              hashes.put(fileNames[i], hash);
          }
          return hashes;
      }