Base::relay PHP Method

    function relay($funcs, $args = NULL)
    {
        foreach (is_array($funcs) ? $funcs : $this->split($funcs) as $func) {
            $args = [$this->call($func, $args)];
        }
        return array_shift($args);
    }

 /**
  * render asset group
  * @param array $assets
  * @return string
  */
 public function renderGroup($assets)
 {
     $out = array();
     foreach ($assets as $asset_type => $collection) {
         if ($this->f3->exists('ASSETS.filter.' . $asset_type, $filters)) {
             if (is_string($filters)) {
                 $filters = $this->f3->split($filters);
             }
             $filters = array_values(array_intersect_key($this->filter, array_flip($filters)));
             $collection = $this->f3->relay($filters, array($collection));
         }
         foreach ($collection as $asset) {
             $out[] = $this->f3->call($this->formatter[$asset_type], array($asset));
         }
     }
     return "\n\t" . implode("\n\t", $out) . "\n";
 }