docs: public void deleteGroup(String key, IPerson deleter) {
  
          if (!canDeleteGroup(deleter, key)) {
              throw new RuntimeAuthorizationException(
                      deleter, IPermission.DELETE_GROUP_ACTIVITY, key);
          }
  
          log.info("Deleting group with key " + key);
  
          // find the current version of this group entity
          IEntityGroup group = GroupService.findGroup(key);
  
          // remove this group from the membership list of any current parent
          // groups
          for (IEntityGroup parent : group.getParentGroups()) {
              parent.removeChild(group);
              parent.updateMembers();
          }
  
          // delete the group
          group.delete();
      }