code: public function filter(Parameters $params, array $permitted = array())
      {
          $this->cleanUnwanted($params, $permitted);
          $this->handleArrays($params, $permitted);
          $this->handleCollections($params, $permitted);
      }
docs: Filter out or throws exception according to the permitted params
  @param  Parameter                     $params
  @param  array                         $permitted
  @throws UnpermittedParameterException when params not permitted are passed in