public function supportedExtensions($dot = false)
    {
        $extensions = array();
        foreach ($this->getHandlers() as $handler) {
            if (!empty($handler['extensions'])) {
                $extensions += array_merge($extensions, (array) $handler['extensions']);
            }
        }

        $extensions = array_unique($extensions);

        if ($dot) {
            $extensions = array_map(function ($value) {
                return ".$value";
            }, $extensions);
        }

        return $extensions;
    }