public function stylesheet($file)
    {
        $dirtypes = ['css', 'stylesheets', 'styles'];
        $asset = '';

        if ($this->_generator->isValidUrl($file)) {
            $asset = $file;
        } else {
            foreach ($dirtypes as $dir) {
                $ext = substr($file, strrpos($file, '.') + 1);
                $file = $file.(($ext != 'css') ? '.css' : '');
                $filepath = base_path().'/assets/'.$dir.'/'.$file;
                $asset = $this->_generator->asset($dir.'/'.$file);

                if (file_exists($filepath)) {
                    break;
                } else {
                    $asset = 'no stylesheet found';
                }
            }
        }

        return '<link rel="stylesheet" type="text/css" href="'.$asset.'">';
    }