code: private String getPackagePid(DigitalObject object) throws Exception {
          for (String pid : object.getPayloadIdList()) {
              if (pid.endsWith(".tfpackage")) {
                  return pid;
              }
          }
          return null;
      }
docs: For the given digital object, find the Fascinator package inside.
  
  @param object The object with a package
  @return String The payload ID of the package, NULL if not found
  @throws Exception if any errors occur