Call to a member function get_type() on string in

public function process($aData, &$aResult, $aConfig)
{
    var_dump($this->cart_object_apps);die;//数组里面是3个对象

    foreach ($this->cart_object_apps as $key => $object) 
    {
        $type_name = $object->get_type();//为什么调用此方法会包上述错误

        //$aResult['object'][$type_name] = $object->getAll(true,$aData);




    }