code: @Override
      public boolean exist(IESigType esigType, String id) {
          return eSigList.indexOf(esigType, id) >= 0;
      }
docs: Tests if the esig item of the specified type and unique id exists.
  
  @param esigType The esig type.
  @param id The unique id.
  @return True if a matching item exists in the list.