public function createFlatArrayWithValuesAsAttributeName($attribute_name)
    {
        $a = [];
        foreach ($this->getCollection() as $key => $object) {
            $object_array = $object->toArray();
            if (isset($object_array[$attribute_name])) {
                $a[$key] = $object_array[$attribute_name];
            }
        }
        return $a;
    }