public function validateAttribute($model, $attribute)
 {
     $identity = UserIdentity::findByLogin($model->login);
     if (!$identity) {
         $this->addError($model, $attribute, Yii::t('user', 'You do not have access to this service. You may have incorrectly entered your username or password. If the reason is not that - talk to your teacher'));
     }
 }
 public static function login($login)
 {
     $identity = UserIdentity::findByLogin($login);
     return Yii::$app->user->login($identity);
 }