Update input-validation.md

docs/guide/input-validation.md

@@ -391,7 +391,7 @@ class CountryValidator extends Validator
     public function validateAttribute($model, $attribute)
     {
         if (!in_array($model->$attribute, ['USA', 'Web'])) {
-            $this->addError($attribute, 'The country must be either "USA" or "Web".');
+            $this->addError($model, $attribute, 'The country must be either "USA" or "Web".');
         }
     }
 }