public function add($pathToAdd, $fileName = null)
    {
        if (is_array($pathToAdd)) {
            foreach ($pathToAdd as $key=>$dir) {
                if (!is_int($key)) {
                    $this->add($dir, $key); }
                else {
                    $this->add($dir);
                }
            }
        } elseif ($this->file->isFile($pathToAdd)) {
            if ($fileName) {
                $this->addFile($pathToAdd, $fileName);
            } else {
                $this->addFile($pathToAdd);
            }
        } else {
            $this->addDir($pathToAdd);
        }

        return $this;
    }