docs: public CmsRelationFilter filterStrong() {
  
          CmsRelationFilter filter = (CmsRelationFilter)clone();
          if (filter.m_types.isEmpty()) {
              filter.m_types.addAll(CmsRelationType.getAllStrong());
          } else {
              filter.m_types = new HashSet<CmsRelationType>(CmsRelationType.filterStrong(filter.m_types));
          }
          return filter;
      }