docs: public IPersonAttributesGroupDefinition getPagsDefinitionByName(IPerson person, String name) {
          IPersonAttributesGroupDefinition rslt = getPagsGroupDefByName(name);
          if (rslt == null) {
              // Better to produce exception?  I'm thinking not, but open-minded.
              return null;
          }
          if (!hasPermission(
                  person,
                  IPermission.VIEW_GROUP_ACTIVITY,
                  rslt.getCompositeEntityIdentifierForGroup().getKey())) {
              throw new RuntimeAuthorizationException(person, IPermission.VIEW_GROUP_ACTIVITY, name);
          }
          logger.debug("Returning PAGS definition '{}' for user '{}'", rslt, person.getUserName());
          return rslt;
      }