In India have Aadhar number an we may need to valid it a input.
So I created a validator for yii2
use yii\validators\Validator;

class TAadharNumberValidator extends Validator
{

public $regExPattern = '/^\d{4}\s\d{4}\s\d{4}$/';

public function validateAttribute($model, $attribute)
{
if (preg_match($this->regExPattern, $model->$attribute)) {
$model->addError($attribute, 'Not valid Aadhar Card Number');
}
}
}