code: public void registerNewChecksums(File featureDir, String fileName, String checksum) {
          ChecksumData checksums = checksumsMap.get(featureDir);
          if (checksums == null) {
              checksums = new ChecksumData();
              checksumsMap.put(featureDir, checksums);
          }
          checksums.registerNewChecksums(fileName, checksum);
      }
docs: Registers a new feature directory's new checksum
  
  @param featureDir the feature directory
  @param fileName the filename for the checksum
  @param checksum the checksum as a String