code: private Group[] getRefsFromFilter(GroupFilter groupFilter) {
          checkNotNull(groupFilter, "Group filter must be not null");
  
          List<Group> groupList = findLazy(groupFilter)
              .map(metadata -> Group.refById(metadata.getId()))
              .collect(toList());
  
          return groupList.toArray(new Group[groupList.size()]);
      }
docs: Extract {@link Group} from {@link GroupFilter}
  @param groupFilter group search criteria
  @return array of groups