public function only($keys)
    {
        $keys = is_array($keys) ? $keys : func_get_args();

        return array_only($this->parameters, $keys);
    }
public function only($keys)
    {
        $keys = is_array($keys) ? $keys : func_get_args();

        return array_only($this->parameters, $keys);
    }
public function only ( $ keys ) { $ keys = is_array ( $ keys ) ? $ keys : func_get_args ( ) ; return array_only ( $ this -> parameters , $ keys ) ; }
Get only certain attributes.

@param string[]|string $keys,...

@return array
Get only certain attributes .