Yii-ish workaround of handling empty multiple select array

Yii 2.0 General Discussions
1

Suppose we have something like this in the controller:


if ($model->load(Yii::$app->request->post())) {


    $model->save();


}

And in the model we have:


['some_ids', 'each', 'rule' => ['integer']],

['some_ids', 'filter', 'filter' => 'array_unique'],

['some_ids', 'filter', 'filter' => [$this, 'checkSomeIds']]

// whatever else

So, what’s the workaround to handle an empty selection using the Yii coding style?

Thanks.