@Override
  public void setGroups(String[] parentGroups, String worldName) {
    backend.setParents(parentGroups, worldName);

    this.clearCache();

    this.callEvent(PermissionEntityEvent.Action.INHERITANCE_CHANGED);
  }
 @Override
 protected String[] getGroupsNamesImpl(String worldName) {
   return backend.getParentNames(worldName);
 }