code: private void checkNotFinished() throws CmsUgcException {
  
          if (m_finished) {
              String message = Messages.get().container(Messages.ERR_FORM_SESSION_ALREADY_FINISHED_0).key(
                  getCmsObject().getRequestContext().getLocale());
              throw new CmsUgcException(CmsUgcConstants.ErrorCode.errInvalidAction, message);
          }
      }
docs: Checks that the session is not finished, and throws an exception otherwise.<p>
  
  @throws CmsUgcException if the session is finished