atk4\data\Model::onlyFields PHP Method

    public function onlyFields($fields = [])
    {
        $this->hook('onlyFields', [&$fields]);
        $this->only_fields = $fields;
        return $this;
    }

 public function testException1fixed()
 {
     $m = new Model();
     $m->addField('name');
     $m->addField('surname');
     $m->onlyFields(['surname']);
     $m->allFields();
     $m['name'] = 5;
 }