public function _export($clause = null, $args = null)
    {
        $args = func_get_args();

        $reflector = new \ReflectionClass(get_class($this));
        $parent = $reflector->getParentClass();
        $method = $parent->getMethod('_export');
        $method->setAccessible('true');
        return $method->invokeArgs($this, $args);
    }