private function doConvertBooleans($item, $callback)
    {
        if (is_array($item)) {
            foreach ($item as $key => $value) {
                $item[$key] = $this->convertSingleBooleanValue($value, $callback);
            }

            return $item;
        }

        return $this->convertSingleBooleanValue($item, $callback);
    }