Let's say you extend `AttributeStampBehavior` and make your own validator.
You can receive direct values in any format, for example:
```php
public function behaviors()
{
	return [
		'mybehavior' => [
			'class' => 'app\behaviors\MyBehavior',
			'attributes' => [
				\yii\db\ActiveRecord::EVENT_BEFORE_INSERT => [
					'some_attribute' => [1,2,3],
				],
			],
		],
	];
}
```
and then in your validator class, you can use the `processValue()` method to for example, serialize the array...