Ouzo\Utilities\Arrays::_flattenKeyRecursively PHP Method

    private static function _flattenKeyRecursively($array, &$result, $parentKey)
    {
        foreach ($array as $key => $value) {
            $itemKey = ($parentKey ? $parentKey . '.' : '') . $key;
            if (is_array($value)) {
                self::_flattenKeyRecursively($value, $result, $itemKey);
            } else {
                $result[$itemKey] = $value;
            }
        }
    }