docs: @Override
      public Set<String> getEntityTypesForGroupType(String groupType) {
  
          // add the group type itself to the allowed list
          Set<String> set = new HashSet<String>();
          set.add(groupType);
  
          /*
           * If the supplied type is a person group, add the person entity type.
           * If the supplied type is a category, add the channel type.  Otherwise,
           * throw an exception.
           *
           * This method will require an update if more entity types are added
           * in the future.
           */
  
          EntityEnum type = EntityEnum.getEntityEnum(groupType);
          if (EntityEnum.GROUP.equals(type)) {
              set.add(EntityEnum.PERSON.toString());
          } else if (EntityEnum.CATEGORY.equals(type)) {
              set.add(EntityEnum.PORTLET.toString());
          } else {
              throw new IllegalArgumentException(
                      "Unable to determine a root entity for group type '" + groupType + "'");
          }
  
          return set;
      }