protected function handleFeatures($fieldName, $features)
    {
        $rOly  = $this->handleFeaturesSingle($fieldName, $features, 'readonly');
        $rDbld = $this->handleFeaturesSingle($fieldName, $features, 'disabled');
        $rNl   = [];
        if (isset($features['include_null']) && in_array($fieldName, $features['include_null'])) {
            $rNl = ['include_null'];
        }
        return array_merge([], $rOly, $rDbld, $rNl);
    }