Argument 1 passed to yii2mod\cart\Cart::add() must be an instance of yii2mod\cart\models\CartItemInterface · Issue #33 · yii2mod/yii2-cart · GitHub
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Getting Started: Creating First Yii Application | The Definitive Guide to Yii 1.1 | Yii PHP Framework
![Getting Started: Creating First Yii Application | The Definitive Guide to Yii 1.1 | Yii PHP Framework Getting Started: Creating First Yii Application | The Definitive Guide to Yii 1.1 | Yii PHP Framework](https://www.yiiframework.com/doc/guide/1.1/en/images/first-app2.png)